Calling dev_set_name with a single paramter causes it to be handled as a
format string. Many callers are passing potentially dynamic string
content, so use "%s" in those cases to avoid any potential accidents,
including wrappers like device_create*() and bdi_register().
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The value passed is 0 in all but "it can never happen" cases (and those
only in a couple of drivers) *and* it would've been lost on the way
out anyway, even if something tried to pass something meaningful.
Just don't bother.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The only part of proc_dir_entry the code outside of fs/proc
really cares about is PDE(inode)->data. Provide a helper
for that; static inline for now, eventually will be moved
to fs/proc, along with the knowledge of struct proc_dir_entry
layout.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The top of <linux/irq.h> has this comment:
* Please do not include this file in generic code. There is currently
* no requirement for any architecture to implement anything held
* within this file.
*
* Thanks. --rmk
Remove inclusion of <linux/irq.h>, to prevent the following compile error
from happening soon:
| include/linux/irq.h:132: error: redefinition of ‘struct irq_data’
| include/linux/irq.h:286: error: redefinition of ‘struct irq_chip’
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: linux-ide@vger.kernel.org
* 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
vfs: make no_llseek the default
vfs: don't use BKL in default_llseek
llseek: automatically add .llseek fop
libfs: use generic_file_llseek for simple_attr
mac80211: disallow seeks in minstrel debug code
lirc: make chardev nonseekable
viotape: use noop_llseek
raw: use explicit llseek file operations
ibmasmfs: use generic_file_llseek
spufs: use llseek in all file operations
arm/omap: use generic_file_llseek in iommu_debug
lkdtm: use generic_file_llseek in debugfs
net/wireless: use generic_file_llseek in debugfs
drm: use noop_llseek
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.
The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.
New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time. Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.
The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.
Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.
Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.
===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
// but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}
@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}
@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}
@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}
@ fops0 @
identifier fops;
@@
struct file_operations fops = {
...
};
@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
.llseek = llseek_f,
...
};
@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
.read = read_f,
...
};
@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
.write = write_f,
...
};
@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
.open = open_f,
...
};
// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
... .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};
@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
... .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};
// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
... .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};
// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};
// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};
@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+ .llseek = default_llseek, /* write accesses f_pos */
};
// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////
@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
.write = write_f,
.read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};
@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};
@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};
@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
The block device drivers have all gained new lock_kernel
calls from a recent pushdown, and some of the drivers
were already using the BKL before.
This turns the BKL into a set of per-driver mutexes.
Still need to check whether this is safe to do.
file=$1
name=$2
if grep -q lock_kernel ${file} ; then
if grep -q 'include.*linux.mutex.h' ${file} ; then
sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
else
sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
fi
sed -i ${file} \
-e "/^#include.*linux.mutex.h/,$ {
1,/^\(static\|int\|long\)/ {
/^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);
} }" \
-e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
-e '/[ ]*cycle_kernel_lock();/d'
else
sed -i -e '/include.*\<smp_lock.h\>/d' ${file} \
-e '/cycle_kernel_lock()/d'
fi
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The open and release block_device_operations are currently
called with the BKL held. In order to change that, we must
first make sure that all drivers that currently rely
on this have no regressions.
This blindly pushes the BKL into all .open and .release
operations for all block drivers to prepare for the
next step. The drivers can subsequently replace the BKL
with their own locks or remove it completely when it can
be shown that it is not needed.
The functions blkdev_get and blkdev_put are the only
remaining users of the big kernel lock in the block
layer, besides a few uses in the ioctl code, none
of which need to serialize with blkdev_{get,put}.
Most of these two functions is also under the protection
of bdev->bd_mutex, including the actual calls to
->open and ->release, and the common code does not
access any global data structures that need the BKL.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
As a preparation for the removal of the big kernel
lock in the block layer, this removes the BKL
from the common ioctl handling code, moving it
into every single driver still using it.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Remove all the trivial wrappers for the cmd_type and cmd_flags fields in
struct requests. This allows much easier grepping for different request
types instead of unwinding through macros.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Ready to get everything using unlocked_ioctl()
For ide_tape we just push down as this is legacy code anyway
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Replace the BKL calls in the chrdev_{open,release} interfaces with a
simple sleeping mutex.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
->read_proc, ->write_proc are going away, ->proc_fops should be used instead.
The only tricky place is IDENTIFY handling: if for some reason
taskfile_lib_get_identify() fails, buffer _is_ changed and at least
first byte is overwritten. Emulate old behaviour with returning
that first byte to userspace and reporting length=1 despite overall -E.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ide-tape used to hit
[ 58.614854] ide-tape: ht0: BUG: Two DSC requests queued!
due to the fact that another rq was being issued while the driver was
waiting for DSC to get set for the device executing ATAPI commands which
set the DSC to 1 to indicate completion.
Here's a sample output of that case:
issue REZERO_UNIT
[ 143.088505] ide-tape: ide_tape_issue_pc: retry #0, cmd: 0x01
[ 143.095122] ide: Enter ide_pc_intr - interrupt handler
[ 143.096118] ide: Packet command completed, 0 bytes transferred
[ 143.106319] ide-tape: ide_tape_callback: cmd: 0x1, dsc: 1, err: 0
[ 143.112601] ide-tape: idetape_postpone_request: cmd: 0x1, dsc_poll_freq: 2000
we stall the ide-tape queue here waiting for DSC
[ 143.119936] ide-tape: ide_tape_read_position: enter
[ 145.119019] ide-tape: idetape_do_request: sector: 4294967295, nr_sectors: 0
and issue the new READ_POSITION rq and hit the check.
[ 145.126247] ide-tape: ht0: BUG: Two DSC requests queued!
[ 145.131748] ide-tape: ide_tape_read_position: BOP - No
[ 145.137059] ide-tape: ide_tape_read_position: EOP - No
Also, ->postponed_rq used to point to that postponed request. To make
things worse, in certain circumstances the rq it was pointing to got
replaced unterneath it by swiftly reusing the same rq from the mempool
of the block layer practically confusing stuff even more.
However, we don't need to keep a pointer to that rq but simply wait for
DSC to be set first before issuing the follow-up request in the drive's
queue. In order to do that, we make idetape_do_request() first check the
DSC and if not set, we stall the drive queue giving the other device on
that IDE channel a chance.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove tape->debug_mask and use drive->debug_mask instead.
There should be no functional change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This error only occurs when IDETAPE_DEBUG_LOG is enabled.
Signed-off-by: Mark de Wever <koraq@xs4all.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
Don't leak kernel stack information through uninitialized structure members.
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Acked-by: Borislav Petkov <petkovbb@gmail.com>.
Signed-off-by: David S. Miller <davem@davemloft.net>
Unsupported requests should be never handed down to device drivers
and the best thing we can do upon discovering such request inside
driver's ->do_request method is to just BUG().
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
* 'for-2.6.31' of git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6: (29 commits)
ide: re-implement ide_pci_init_one() on top of ide_pci_init_two()
ide: unexport ide_find_dma_mode()
ide: fix PowerMac bootup oops
ide: skip probe if there are no devices on the port (v2)
sl82c105: add printk() logging facility
ide-tape: fix proc warning
ide: add IDE_DFLAG_NIEN_QUIRK device flag
ide: respect quirk_drives[] list on all controllers
hpt366: enable all quirks for devices on quirk_drives[] list
hpt366: sync quirk_drives[] list with pdc202xx_{new,old}.c
ide: remove superfluous SELECT_MASK() call from do_rw_taskfile()
ide: remove superfluous SELECT_MASK() call from ide_driveid_update()
icside: remove superfluous ->maskproc method
ide-tape: fix IDE_AFLAG_* atomic accesses
ide-tape: change IDE_AFLAG_IGNORE_DSC non-atomically
pdc202xx_old: kill resetproc() method
pdc202xx_old: don't call pdc202xx_reset() on IRQ timeout
pdc202xx_old: use ide_dma_test_irq()
ide: preserve Host Protected Area by default (v2)
ide-gd: implement block device ->set_capacity method (v2)
...
* 'for-2.6.31' of git://git.kernel.dk/linux-2.6-block: (153 commits)
block: add request clone interface (v2)
floppy: fix hibernation
ramdisk: remove long-deprecated "ramdisk=" boot-time parameter
fs/bio.c: add missing __user annotation
block: prevent possible io_context->refcount overflow
Add serial number support for virtio_blk, V4a
block: Add missing bounce_pfn stacking and fix comments
Revert "block: Fix bounce limit setting in DM"
cciss: decode unit attention in SCSI error handling code
cciss: Remove no longer needed sendcmd reject processing code
cciss: change SCSI error handling routines to work with interrupts enabled.
cciss: separate error processing and command retrying code in sendcmd_withirq_core()
cciss: factor out fix target status processing code from sendcmd functions
cciss: simplify interface of sendcmd() and sendcmd_withirq()
cciss: factor out core of sendcmd_withirq() for use by SCSI error handling code
cciss: Use schedule_timeout_uninterruptible in SCSI error handling code
block: needs to set the residual length of a bidi request
Revert "block: implement blkdev_readpages"
block: Fix bounce limit setting in DM
Removed reference to non-existing file Documentation/PCI/PCI-DMA-mapping.txt
...
Manually fix conflicts with tracing updates in:
block/blk-sysfs.c
drivers/ide/ide-atapi.c
drivers/ide/ide-cd.c
drivers/ide/ide-floppy.c
drivers/ide/ide-tape.c
include/trace/events/block.h
kernel/trace/blktrace.c
These flags used to be bit numbers and now are single bits in the
->atapi_flags vector. Use them properly.
Spotted-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
There are two sites where the flag is being changed: ide_retry_pc
and idetape_do_request. Both codepaths are protected by hwif->busy
(ide_lock_port) and therefore we shouldn't need the atomic accesses.
Spotted-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
In commit c3a4d78c58, while introducing
rq->resid_len, the default value of residue count was changed from
full count to zero. The conversion was done under the assumption that
when a request fails residue count wasn't defined. However, Boaz and
James pointed out that this wasn't true and the residue count should
be preserved for failed requests too.
This patchset restores the original behavior by setting rq->resid_len
to blk_rq_bytes(rq) on request start and restoring explicit clearing
in affected drivers. While at it, take advantage of the fact that
rq->resid_len is set to full count where applicable.
* ide-cd: rq->resid_len cleared on pc success
* mptsas: req->resid_len cleared on success
* sas_expander: rsp/req->resid_len cleared on success
* mpt2sas_transport: req->resid_len cleared on success
* ide-cd, ide-tape, mptsas, sas_host_smp, mpt2sas_transport, ub: take
advantage of initial full count to simplify code
Boaz Harrosh spotted bug in resid_len initialization. Fixed as
suggested.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Borislav Petkov <petkovbb@googlemail.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This error only occurs when IDETAPE_DEBUG_LOG is enabled.
Signed-off-by: Mark de Wever <koraq@xs4all.nl>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Now after all users of pc->buf have been converted, remove the 64B buffer
embedded in each packet command.
There should be no functional change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
ide-tape used to issue READ POSITION in several places and the
evaluation of the returned READ POSITION data was done in the
->pc_callback. Convert it to use local buffer and move that
evaluation chunk in the idetape_read_position(). Additionally, fold
idetape_create_read_position_cmd() into it, too, thus concentrating READ
POSITION handling in one method only and making all places call that.
Finally, mv {idetape,ide_tape}_read_position.
There should be no functional change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Access the sense buffer through the bio in ->pc_callback method thus
alleviating the need for the pc->buf pointer.
There should be no functional change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
This is in preparation of removing ide_atapi_pc. Expose the buffer as an
argument to ide_queue_pc_tail with later replacing it with local buffer
or even kmalloc'ed one if needed due to stack usage constraints.
Also, add the possibility of passing a NULL-ptr buffer for cmds which
don't transfer data besides the cdb. While at it, switch to local buffer
in idetape_get_mode_sense_results().
There should be no functional change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
This is in preparation for removing ide_atapi_pc.
There should be no functional change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Now that we have rq->resid_len, use it to account partial completion
amount during the lifetime of an rq, decrementing it on each successful
transfer. As a result, get rid of now unused pc->xferred.
While at it, remove noisy debug call in ide_prep_sense.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
After the recent struct request cleanups, blk_rq_bytes() is guaranteed
to be valid and is the current total length of the rq's bio. Use that
instead of pc->req_xfer in the do_request() path after the command has
been queued
The remaining usage of pc->req_xfer now is only until we map the rq to a
bio.
While at it:
- remove local caching of rq completion length in ide_tape_issue_pc()
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
ide-tape had a potential bug for fs requests when preparing the command
packet: it was writing the transfer length as a number of fixed blocks.
However, the block layer implies 512 byte blocks and ide-tape can have
other block sizes so account for that too.
ide-floppy does this calculation properly with the block size factor
(floppy->bs_factor).
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
With recent unification of fields, it's now guaranteed that
rq->data_len always equals blk_rq_bytes(). Convert all direct users
to accessors.
[ Impact: convert direct rq->data_len usages to blk_rq_bytes() ]
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
ide doesn't manipulate request fields anymore and thus all hard and
their soft equivalents are always equal. Convert all references to
accessors.
[ Impact: use pos and nr_sectors accessors ]
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
rq->data_len served two purposes - the length of data buffer on issue
and the residual count on completion. This duality creates some
headaches.
First of all, block layer and low level drivers can't really determine
what rq->data_len contains while a request is executing. It could be
the total request length or it coulde be anything else one of the
lower layers is using to keep track of residual count. This
complicates things because blk_rq_bytes() and thus
[__]blk_end_request_all() relies on rq->data_len for PC commands.
Drivers which want to report residual count should first cache the
total request length, update rq->data_len and then complete the
request with the cached data length.
Secondly, it makes requests default to reporting full residual count,
ie. reporting that no data transfer occurred. The residual count is
an exception not the norm; however, the driver should clear
rq->data_len to zero to signify the normal cases while leaving it
alone means no data transfer occurred at all. This reverse default
behavior complicates code unnecessarily and renders block PC on some
drivers (ide-tape/floppy) unuseable.
This patch adds rq->resid_len which is used only for residual count.
While at it, remove now unnecessasry blk_rq_bytes() caching in
ide_pc_intr() as rq->data_len is not changed anymore.
Boaz : spotted missing conversion in osd
Sergei : spotted too early conversion to blk_rq_bytes() in ide-tape
[ Impact: cleanup residual count handling, report 0 resid by default ]
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Darrick J. Wong <djwong@us.ibm.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
rq->sector is set to the tape->first_frame but it's never actually
used and not even in the correct unit (512 byte sectors). Don't set
it.
[ Impact: cleanup ]
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Borislav Petkov <petkovbb@gmail.com>
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Impact: remove fields and code paths which are no longer necessary
Now that ide-tape uses standard mechanisms to transfer data, special
case handling for bh handling can be dropped from ide-atapi. Drop the
followings.
* pc->cur_pos, b_count, bh and b_data
* drive->pc_update_buffers() and pc_io_buffers().
Signed-off-by: Tejun Heo <tj@kernel.org>
Impact: cleanup
idetape_chrdev_read/write() functions are unnecessarily complex when
everything can be handled in a single loop. Collapse
idetape_add_chrdev_read/write_request() into the rw functions and
simplify the implementation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Impact: cleanup
Byte size is what most issue functions deal with, make
idetape_queue_rw_tail() and its wrappers take byte size instead of
sector counts. idetape_chrdev_read() and write() functions are
converted to use tape->buffer_size instead of ctl from tape->cap.
This cleans up code a little bit and will ease the next r/w
reimplementation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Impact: kill now unnecessary idetape_bh
With everything using standard mechanisms, there is no need for
idetape_bh anymore. Kill it and use tape->buf, cur and valid to
describe data buffer instead.
Changes worth mentioning are...
* idetape_queue_rq_tail() now always queue tape->buf and and adjusts
buffer state properly before completion.
* idetape_pad_zeros() clears the buffer only once.
Signed-off-by: Tejun Heo <tj@kernel.org>
Impact: use standard way to transfer data
ide-tape uses rq in an interesting way. For r/w requests, rq->special
is used to carry a private buffer management structure idetape_bh and
rq->nr_sectors and current_nr_sectors are initialized to the number of
idetape blocks which isn't necessary 512 bytes. Also,
rq->current_nr_sectors is used to report back the residual count in
units of idetape blocks.
This peculiarity taxes both block layer and ide. ide-atapi has
different paths and hooks to accomodate it and what a rq means becomes
quite confusing and making changes at the block layer becomes quite
difficult and error-prone.
This patch makes ide-tape use bio instead. With the previous patch,
ide-tape currently is using single contiguos buffer so replacing it
isn't difficult. Data buffer is mapped into bio using
blk_rq_map_kern() in idetape_queue_rw_tail(). idetape_io_buffers()
and idetape_update_buffers() are dropped and pc->bh is set to null to
tell ide-atapi to use standard data transfer mechanism and idetape_bh
byte counts are updated by the issuer on completion using the residual
count.
This change also nicely removes the FIXME in ide_pc_intr() where
ide-tape rqs need to be completed using ide_rq_bytes() instead of
blk_rq_bytes() (although this didn't really matter as the request
didn't have bio).
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Impact: simpler buffer allocation and handling, kills OOM, fix DMA transfers
ide-tape has its own multiple buffer mechanism using struct
idetape_bh. It allocates buffer with decreasing order-of-two
allocations so that it results in minimum number of segments.
However, the implementation is quite complex and works in a way that
no other block or ide driver works necessitating a lot of special case
handling.
The benefit this complex allocation scheme brings is questionable as
PIO or DMA the number of segments (16 maximum) doesn't make any
noticeable difference and it also doesn't negate the need for multiple
order allocation which can fail under memory pressure or high
fragmentation although it does lower the highest order necessary by
one when the buffer size isn't power of two.
As the first step to remove the custom buffer management, this patch
makes ide-tape allocate single continous buffer. The maximum order is
four. I doubt the change would cause any trouble but if it ever
matters, it should be converted to regular sg mechanism like everyone
else and even in that case dropping custom buffer handling and moving
to standard mechanism first make sense as an intermediate step.
This patch makes the first bh to contain the whole buffer and drops
multi bh handling code. Following patches will make further changes.
This patch has the side effect of killing OOM triggered by allocation
path and fixing DMA transfers. Previously, bug in alloc path
triggered OOM on command issue and commands were passed to DMA engine
without DMA-mapping all the segments.
Signed-off-by: Tejun Heo <tj@kernel.org>
Impact: allow residual count implementation in ->pc_callback()
rq->data_len has two duties - carrying the number of input bytes on
issue and carrying residual count back to the issuer on completion.
ide-atapi completion callback ->pc_callback() is the right place to do
this but currently ide-atapi depends on rq->data_len carrying the
original request size after calling ->pc_callback() to complete the pc
request.
This patch makes ide_pc_intr(), ide_tape_issue_pc() and
ide_floppy_issue_pc() cache length to complete before calling
->pc_callback() so that it can modify rq->data_len as necessary.
Note: As using rq->data_len for two purposes can make cases like this
incorrect in subtle ways, future changes will introduce separate
field for residual count.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Impact: fix infinite retry loop
After a command failed, ide-tape and floppy inserts REQUEST_SENSE in
front of the failed command and according to the result, sets
pc->retries, flags and errors. After REQUEST_SENSE is complete, the
failed command is again at the front of the queue and if the verdict
was to terminate the request, the issue functions tries to complete it
directly by calling drive->pc_callback() and returning ide_stopped.
However, drive->pc_callback() doesn't complete a request. It only
prepares for completion of the request. As a result, this creates an
infinite loop where the failed request is retried perpetually.
Fix it by actually ending the request by calling ide_complete_rq().
Signed-off-by: Tejun Heo <tj@kernel.org>
Kees Cook