From: Sagi Grimberg Date: Wed, 5 Mar 2014 12:05:09 +0000 (+0200) Subject: Target/sbc: Fix sbc_copy_prot for offset scatters X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=16c0ae028989df40bdab46b7f241d331ddc97c59;p=deliverable%2Flinux.git Target/sbc: Fix sbc_copy_prot for offset scatters When copying between device and command protection scatters we must take into account that device scatters might be offset and we might copy outside scatter range. Thus for each cmd prot scatter we must take the min between cmd prot scatter, dev prot scatter, and whats left (and loop in case we havn't copied enough from/to cmd prot scatter). Example (single t_prot_sg of len 2048): kernel: sbc_dif_copy_prot: se_cmd=ffff880380aaf970, left=2048, len=2048, dev_prot_sg_offset=3072, dev_prot_sg_len=4096 kernel: isert: se_cmd=ffff880380aaf970 PI error found type 0 at sector 0x2600 expected 0x0 vs actual 0x725f, lba=2580 Instead of copying 2048 from offset 3072 (copying junk outside sg limit 4096), we must to copy 1024 and continue to next sg until we complete cmd prot scatter. This issue was found using iSER T10-PI offload over rd_mcp (wasn't discovered with fileio since file_dev prot sglists are never offset). Changes from v1: - Fix sbc_copy_prot copy length miss-calculation Changes from v0: - Removed psg->offset consideration for psg_len computation - Removed sg->offset consideration for offset condition - Added copied consideraiton for len computation - Added copied offset to paddr when doing memcpy Signed-off-by: Sagi Grimberg Signed-off-by: Nicholas Bellinger --- diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c index 42f18fc1067b..77e6531fb0a1 100644 --- a/drivers/target/target_core_sbc.c +++ b/drivers/target/target_core_sbc.c @@ -1079,25 +1079,31 @@ sbc_dif_copy_prot(struct se_cmd *cmd, unsigned int sectors, bool read, left = sectors * dev->prot_length; for_each_sg(cmd->t_prot_sg, psg, cmd->t_prot_nents, i) { - - len = min(psg->length, left); - if (offset >= sg->length) { - sg = sg_next(sg); - offset = 0; - } + unsigned int psg_len, copied = 0; paddr = kmap_atomic(sg_page(psg)) + psg->offset; - addr = kmap_atomic(sg_page(sg)) + sg->offset + offset; - - if (read) - memcpy(paddr, addr, len); - else - memcpy(addr, paddr, len); - - left -= len; - offset += len; + psg_len = min(left, psg->length); + while (psg_len) { + len = min(psg_len, sg->length - offset); + addr = kmap_atomic(sg_page(sg)) + sg->offset + offset; + + if (read) + memcpy(paddr + copied, addr, len); + else + memcpy(addr, paddr + copied, len); + + left -= len; + offset += len; + copied += len; + psg_len -= len; + + if (offset >= sg->length) { + sg = sg_next(sg); + offset = 0; + } + kunmap_atomic(addr); + } kunmap_atomic(paddr); - kunmap_atomic(addr); } }