From: Tejun Heo <htejun@gmail.com>
Date: Mon, 20 Feb 2006 14:48:37 +0000 (+0900)
Subject: [PATCH] libata: fix WARN_ON() condition in *_fill_sg()
X-Git-Tag: v2.6.16-rc5~67^2~2
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=9ae61c6cb69f5251d160576c324948805f97e901;p=linux-2.6-omap-h63xx.git

[PATCH] libata: fix WARN_ON() condition in *_fill_sg()

For ATAPI commands, padding can reduce qc->n_elem by one and thus to
zero making assert(qc->n_elem > 0)'s in ata_fill_sg() and qs_fill_sg()
fail for legal commands.  This patch fixes the assert()'s to take
qc->pad_len into account.

Although the condition check seems a bit excessive, as this part of
code isn't still stable yet, I think it's worth to keep those.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
---

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 7ddd5a69352..bbac87a13d5 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2570,7 +2570,7 @@ static void ata_fill_sg(struct ata_queued_cmd *qc)
 	unsigned int idx;
 
 	assert(qc->__sg != NULL);
-	assert(qc->n_elem > 0);
+	assert(qc->n_elem > 0 || qc->pad_len > 0);
 
 	idx = 0;
 	ata_for_each_sg(sg, qc) {
diff --git a/drivers/scsi/sata_qstor.c b/drivers/scsi/sata_qstor.c
index de05e2883f9..80480f0fb2b 100644
--- a/drivers/scsi/sata_qstor.c
+++ b/drivers/scsi/sata_qstor.c
@@ -277,7 +277,7 @@ static unsigned int qs_fill_sg(struct ata_queued_cmd *qc)
 	u8 *prd = pp->pkt + QS_CPB_BYTES;
 
 	assert(qc->__sg != NULL);
-	assert(qc->n_elem > 0);
+	assert(qc->n_elem > 0 || qc->pad_len > 0);
 
 	nelem = 0;
 	ata_for_each_sg(sg, qc) {