The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200213003703.GA4177@embeddedor.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.
Also, because there is no need to save the file dentry, remove the
variable that was saving it as it was never even being used once set.
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: dmaengine@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This patch makes the comment header of Broadcom SBA RAID driver
similar to the GPL comment header used across Broadcom driver
sources.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Each mailbox channel used by Broadcom SBA RAID driver is
a separate HW ring.
Currently, Broadcom SBA RAID driver creates one DMA channel
using one or more mailbox channels. When we are using more
than one mailbox channels for a DMA channel, the sba_request
are distributed evenly among multiple mailbox channels which
results in sba_request being completed out-of-order.
The above described out-of-order completion of sba_request
breaks the dma_async_is_complete() API because it assumes
DMA cookies are completed in orderly fashion.
To ensure correct behaviour of dma_async_is_complete() API,
this patch updates Broadcom SBA RAID driver to use only
single mailbox channel. If additional mailbox channels are
specified in DT then those will be ignored.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
As-per documentation in driver/dma/dmaengine.h, the
dma_cookie_complete() API should be called with lock
held.
This patch ensures that Broadcom SBA RAID driver calls
the dma_cookie_complete() API with reqs_lock held.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
The SBA_REQUEST_STATE_COMPLETED state was added to keep track
of sba_request which got completed but cannot be freed because
underlying Async Tx descriptor was not ACKed by DMA client.
Instead of above, we can free the sba_request with non-ACKed
Async Tx descriptor and sba_alloc_request() will ensure that
it always allocates sba_request with ACKed Async Tx descriptor.
This alternate approach makes SBA_REQUEST_STATE_COMPLETED state
redundant hence this patch removes it.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
We should explicitly ACK mailbox message because after
sending message we can know the send status via error
attribute of brcm_message.
This will also help SBA-RAID to use "txdone_ack" method
whenever mailbox controller supports it.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This patch adds debugfs support to report stats via debugfs
which in-turn will help debug hang or error situations.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
The SBA_REQUEST_STATE_RECEIVED state is now redundant because
received sba_request are immediately freed or moved to completed
list in sba_process_received_request().
This patch removes redundant SBA_REQUEST_STATE_RECEIVED state.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Currently, sba_process_deferred_requests() handles both pending
and completed sba_request which is unnecessary overhead for
sba_issue_pending() because completed sba_request handling is
not required in sba_issue_pending().
This patch breaks sba_process_deferred_requests() into two parts
sba_process_received_request() and _sba_process_pending_requests().
The sba_issue_pending() will only process pending sba_request
by calling _sba_process_pending_requests(). This will improve
sba_issue_pending().
The sba_receive_message() will only process received sba_request
by calling sba_process_received_request() for each received
sba_request. The sba_process_received_request() will also call
_sba_process_pending_requests() after handling received sba_request
because we might have pending sba_request not submitted by previous
call to sba_issue_pending().
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
We should pre-ack async tx descriptor at time of
allocating sba_request (just like other RAID drivers).
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
When setting up RAID array on several NVMe disks we observed that
sba_alloc_request() start failing (due to no free requests left)
and RAID array setup becomes very slow.
To improve performance, we do mbox channel peek when we have
no free requests. This improves performance of RAID array setup
because mbox requests that were completed but not processed by
mbox completion worker will be processed immediately by mbox
channel peek.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
We should allocate DMA channel resources before registering the
DMA device in sba_probe() because we can get DMA request soon
after registering the DMA device. If DMA channel resources are
not allocated before first DMA request then SBA-RAID driver will
crash.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
The pending sba_request list can become very long in real-life usage
(e.g. setting up RAID array) which can cause sba_issue_pending() to
run for long duration.
This patch adds common sba_process_deferred_requests() to process
few completed and pending requests so that it finishes in short
duration. We use this common sba_process_deferred_requests() in
both sba_issue_pending() and sba_receive_message().
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Currently, we have only 1024 free sba_request created
by sba_prealloc_channel_resources(). This is too low
and the prep_xxx() callbacks start failing more often
at time of RAID array setup over NVMe disks.
This patch sets number of free sba_request created by
sba_prealloc_channel_resources() to be:
<number_of_mailbox_channels> x 8192
Due to above, we will have sufficient number of free
sba_request and prep_xxx() callbacks failing is very
unlikely.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Currently, we cannot have any arbitrary number of free sba_request
because sba_prealloc_channel_resources() allocates an array of
sba_request using devm_kcalloc() and kcalloc() cannot provide
memory beyond certain size.
This patch removes "reqs" (sba_request array) from sba_device
and makes "cmds" as variable array (instead of pointer) in
sba_request. This helps sba_prealloc_channel_resources() to
allocate sba_request and associated SBA command in one allocation
which in-turn allows arbitrary number of free sba_request.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
The reqs_free_count member of sba_device is not used anywhere
hence no point in tracking number of free sba_request.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Both resp and resp_dma are redundant in sba_request because
resp is unused and resp_dma carries same information present
in tx.phys of sba_request. This patch removes both resp and
resp_dma from sba_request.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
The next_count in sba_request is redundant because same information
is captured by next_pending_count. This patch removes next_count
from sba_request.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This patch merges sba_request state and fence into common
sba_request flags. The sba_request flags not only saves
memory but it can also be extended in-future without adding
new members.
We also make each sba_request state as separate bit in
sba_request flags to help debugging situations where a
sba_request is accidently in two states.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
We don't require to hold "sba->reqs_lock" for long-time
in sba_alloc_request() because lock protection is not
required when initializing members of "struct sba_request".
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This patch does following improvments to comments:
1. Make section comments consistent across the driver by
avoiding " SBA " in some of the comments
2. Add/update few more section comments
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This driver builds with warnings which can be fixed by making these
functions static.
CC [M] drivers/dma/bcm-sba-raid.o
drivers/dma/bcm-sba-raid.c:786:1: warning: no previous prototype for ‘sba_prep_dma_xor_req’ [-Wmissing-prototypes]
sba_prep_dma_xor_req(struct sba_device *sba,
^
drivers/dma/bcm-sba-raid.c:995:1: warning: no previous prototype for ‘sba_prep_dma_pq_req’ [-Wmissing-prototypes]
sba_prep_dma_pq_req(struct sba_device *sba, dma_addr_t off,
^
drivers/dma/bcm-sba-raid.c:1247:1: warning: no previous prototype for ‘sba_prep_dma_pq_single_req’ [-Wmissing-prototypes]
sba_prep_dma_pq_single_req(struct sba_device *sba, dma_addr_t off,
^
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Req is never null on at the point of the null check, so
remove this redundant check and just return &req->tx.
Detected by CoverityScan, CID#1436147 ("Logically dead code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
The Broadcom stream buffer accelerator (SBA) provides offloading
capabilities for RAID operations. This SBA offload engine is
accessible via Broadcom SoC specific ring manager.
This patch adds Broadcom SBA RAID driver which provides one
DMA device with RAID capabilities using one or more Broadcom
SoC specific ring manager channels. The SBA RAID driver in its
current shape implements memcpy, xor, and pq operations.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Gustavo A. R. Silva