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net_dma: poll for a descriptor after allocation failure 

Handle descriptor allocation failures by polling for a descriptor.  The
driver will force forward progress when polled.  In the best case this
polling interval will be the time it takes for one dma memcpy
transaction to complete.  In the worst case, channel hang, we will need
to wait 100ms for the cleanup watchdog to fire (ioatdma driver).

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2009-09-08 12:02:15 -07:00
parent a309218ace
commit 4b652f0db3
1 changed files with 10 additions and 0 deletions
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10
drivers/dma/iovlock.c
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@ -183,6 +183,11 @@ dma_cookie_t dma_memcpy_to_iovec(struct dma_chan *chan, struct iovec *iov,
iov_byte_offset,
kdata,
copy);
/* poll for a descriptor slot */
if (unlikely(dma_cookie < 0)) {
dma_async_issue_pending(chan);
continue;
}
len -= copy;
iov[iovec_idx].iov_len -= copy;
@ -248,6 +253,11 @@ dma_cookie_t dma_memcpy_pg_to_iovec(struct dma_chan *chan, struct iovec *iov,
page,
offset,
copy);
/* poll for a descriptor slot */
if (unlikely(dma_cookie < 0)) {
dma_async_issue_pending(chan);
continue;
}
len -= copy;
iov[iovec_idx].iov_len -= copy;