[ add Vinod's korg address ] On Tue, May 29, 2018 at 3:37 PM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > [ adding linux-raid ] > > Apologies for the delay, the recent ping from Kees made me take a closer look. > > On Sat, May 5, 2018 at 12:58 AM, Kyle Spiers <ksspiers@xxxxxxxxxx> wrote: >> In the quest to remove VLAs from the kernel[1], this moves the >> allocation of coefs and blocks from the stack to being kmalloc()ed. >> >> [1] https://lkml.org/lkml/2018/3/7/621 >> >> Signed-off-by: Kyle Spiers <ksspiers@xxxxxxxxxx> >> --- >> Forgot to add slab.h >> --- >> crypto/async_tx/async_pq.c | 18 ++++++++++++++---- >> crypto/async_tx/raid6test.c | 9 ++++++++- >> 2 files changed, 22 insertions(+), 5 deletions(-) >> >> diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c >> index 56bd612927ab..af1912313a23 100644 >> --- a/crypto/async_tx/async_pq.c >> +++ b/crypto/async_tx/async_pq.c >> @@ -194,9 +194,9 @@ async_gen_syndrome(struct page **blocks, unsigned int offset, int disks, >> (src_cnt <= dma_maxpq(device, 0) || >> dma_maxpq(device, DMA_PREP_CONTINUE) > 0) && >> is_dma_pq_aligned(device, offset, 0, len)) { >> - struct dma_async_tx_descriptor *tx; >> + struct dma_async_tx_descriptor *tx = NULL; >> enum dma_ctrl_flags dma_flags = 0; >> - unsigned char coefs[src_cnt]; >> + unsigned char *coefs; >> int i, j; >> >> /* run the p+q asynchronously */ >> @@ -207,6 +207,9 @@ async_gen_syndrome(struct page **blocks, unsigned int offset, int disks, >> * sources and update the coefficients accordingly >> */ >> unmap->len = len; >> + coefs = kmalloc_array(src_cnt, sizeof(*coefs), GFP_KERNEL); > > At a minimum this needs to be GFP_NOIO since raid may be in the > page-reclaim path. > > However, I think it may be better to allocate this with the rest of > the stripe resources and pass it in as a scratch buffer. See the usage > / implementation of scribble_alloc() in drivers/md/raid5.c.
