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usb: wusbcore: resource cleanup fix in __wa_xfer_setup_segs 

This patch updates __wa_xfer_setup_segs error path to only clean up the
xfer->seg entry that it failed to create and then set that entry to
NULL.  wa_xfer_destroy will clean up the remaining xfer->segs that were
fully created.  It also moves the code to create the dto sg list to an
out of line function to make __wa_xfer_setup_segs easier to read.  Prior
to this change, __wa_xfer_setup_segs would clean up all entries in the
xfer->seg array in case of an error but it did not set them to NULL.
This resulted in a double free when wa_xfer_destroy was eventually
called by the higher level error handler.

Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thomas Pugliese 2013-09-26 14:08:14 -05:00 committed by Greg Kroah-Hartman
parent d993670ca9
commit ffd6d17ddb
1 changed files with 65 additions and 52 deletions
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117
drivers/usb/wusbcore/wa-xfer.c
View File

@ -635,9 +635,11 @@ static void wa_seg_tr_cb(struct urb *urb)
}
}
/* allocate an SG list to store bytes_to_transfer bytes and copy the
/*
* Allocate an SG list to store bytes_to_transfer bytes and copy the
* subset of the in_sg that matches the buffer subset
* we are about to transfer. */
* we are about to transfer.
*/
static struct scatterlist *wa_xfer_create_subset_sg(struct scatterlist *in_sg,
const unsigned int bytes_transferred,
const unsigned int bytes_to_transfer, unsigned int *out_num_sgs)
@ -715,6 +717,55 @@ static struct scatterlist *wa_xfer_create_subset_sg(struct scatterlist *in_sg,
return out_sg;
}
/*
* Populate buffer ptr and size, DMA buffer or SG list for the dto urb.
*/
static int __wa_populate_dto_urb(struct wa_xfer *xfer,
struct wa_seg *seg, size_t buf_itr_offset, size_t buf_itr_size)
{
int result = 0;
if (xfer->is_dma) {
seg->dto_urb->transfer_dma =
xfer->urb->transfer_dma + buf_itr_offset;
seg->dto_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
seg->dto_urb->sg = NULL;
seg->dto_urb->num_sgs = 0;
} else {
/* do buffer or SG processing. */
seg->dto_urb->transfer_flags &=
~URB_NO_TRANSFER_DMA_MAP;
/* this should always be 0 before a resubmit. */
seg->dto_urb->num_mapped_sgs = 0;
if (xfer->urb->transfer_buffer) {
seg->dto_urb->transfer_buffer =
xfer->urb->transfer_buffer +
buf_itr_offset;
seg->dto_urb->sg = NULL;
seg->dto_urb->num_sgs = 0;
} else {
seg->dto_urb->transfer_buffer = NULL;
/*
* allocate an SG list to store seg_size bytes
* and copy the subset of the xfer->urb->sg that
* matches the buffer subset we are about to
* read.
*/
seg->dto_urb->sg = wa_xfer_create_subset_sg(
xfer->urb->sg,
buf_itr_offset, buf_itr_size,
&(seg->dto_urb->num_sgs));
if (!(seg->dto_urb->sg))
result = -ENOMEM;
}
}
seg->dto_urb->transfer_buffer_length = buf_itr_size;
return result;
}
/*
* Allocate the segs array and initialize each of them
*
@ -762,48 +813,13 @@ static int __wa_xfer_setup_segs(struct wa_xfer *xfer, size_t xfer_hdr_size)
usb_sndbulkpipe(usb_dev,
dto_epd->bEndpointAddress),
NULL, 0, wa_seg_dto_cb, seg);
if (xfer->is_dma) {
seg->dto_urb->transfer_dma =
xfer->urb->transfer_dma + buf_itr;
seg->dto_urb->transfer_flags |=
URB_NO_TRANSFER_DMA_MAP;
seg->dto_urb->transfer_buffer = NULL;
seg->dto_urb->sg = NULL;
seg->dto_urb->num_sgs = 0;
} else {
/* do buffer or SG processing. */
seg->dto_urb->transfer_flags &=
~URB_NO_TRANSFER_DMA_MAP;
/* this should always be 0 before a resubmit. */
seg->dto_urb->num_mapped_sgs = 0;
if (xfer->urb->transfer_buffer) {
seg->dto_urb->transfer_buffer =
xfer->urb->transfer_buffer +
buf_itr;
seg->dto_urb->sg = NULL;
seg->dto_urb->num_sgs = 0;
} else {
/* allocate an SG list to store seg_size
bytes and copy the subset of the
xfer->urb->sg that matches the
buffer subset we are about to read.
*/
seg->dto_urb->sg =
wa_xfer_create_subset_sg(
xfer->urb->sg,
buf_itr, buf_itr_size,
&(seg->dto_urb->num_sgs));
/* fill in the xfer buffer information. */
result = __wa_populate_dto_urb(xfer, seg,
buf_itr, buf_itr_size);
if (!(seg->dto_urb->sg)) {
seg->dto_urb->num_sgs = 0;
goto error_sg_alloc;
}
seg->dto_urb->transfer_buffer = NULL;
}
}
seg->dto_urb->transfer_buffer_length = buf_itr_size;
if (result < 0)
goto error_seg_outbound_populate;
}
seg->status = WA_SEG_READY;
buf_itr += buf_itr_size;
@ -811,20 +827,17 @@ static int __wa_xfer_setup_segs(struct wa_xfer *xfer, size_t xfer_hdr_size)
}
return 0;
error_sg_alloc:
/*
* Free the memory for the current segment which failed to init.
* Use the fact that cnt is left at were it failed. The remaining
* segments will be cleaned up by wa_xfer_destroy.
*/
error_seg_outbound_populate:
usb_free_urb(xfer->seg[cnt]->dto_urb);
error_dto_alloc:
kfree(xfer->seg[cnt]);
cnt--;
xfer->seg[cnt] = NULL;
error_seg_kmalloc:
/* use the fact that cnt is left at were it failed */
for (; cnt >= 0; cnt--) {
if (xfer->seg[cnt] && xfer->is_inbound == 0) {
usb_free_urb(xfer->seg[cnt]->dto_urb);
kfree(xfer->seg[cnt]->dto_urb->sg);
}
kfree(xfer->seg[cnt]);
}
error_segs_kzalloc:
return result;
}