[PATCH 10/11] target: do not submit a zero-bio I/O request

From: Paolo Bonzini
Date: Fri Sep 07 2012 - 11:32:31 EST


scsi_setup_fs_cmnd does not like to receive requests with no
bios attached to it. Special-case zero-length reads and writes,
by not submitting any bio.

Testcase: sg_raw /dev/sdb 28 00 00 00 00 00 00 00 00 00
should not fail
panics with the rest of the series but not this patch
behaves correctly without or with this series

---
drivers/target/target_core_iblock.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 9ba4954..167c5e1 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -657,6 +657,12 @@ static int iblock_execute_rw(struct se_cmd *cmd)
goto fail;
cmd->priv = ibr;

+ if (!sgl_nents) {
+ atomic_set(&ibr->pending, 1);
+ iblock_complete_cmd(cmd);
+ return 0;
+ }
+
bio = iblock_get_bio(cmd, block_lba, sgl_nents);
if (!bio)
goto fail_free_ibr;
--
1.7.1


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