SG: work with the SCSI fixed maximum allocations

PATCH New James Bottomley 1 participant 1 message Jan 14, 2008

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James Bottomley

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2008-01-14 16:04 UTC #0 lore raw

PATCH 1/1 SG: work with the SCSI fixed maximum allocations

Boaz pointed out that the current sg table code will bug in the SCSI index function because it assumes a larger sized allocator that SCSI possesses. This patch fixes the issue.

James

---

Quoted 1 line

From 258aae00284d61786758d9e740df08cc4b916f96 Mon Sep 17 00:00:00 2001

From: James Bottomley <[email protected]>
Date: Sun, 13 Jan 2008 14:15:28 -0600
Subject: SG: work with the SCSI fixed maximum allocations

SCSI sg table allocation has a maximum size (of SCSI_MAX_SG_SEGMENTS, currently 128) and this will cause a BUG_ON() in SCSI if something tries an allocation over it. This patch adds a size limit to the chaining allocator to allow the specification of the maximum allocation size for chaining, so we always chain in units of the maximum SCSI allocation size.

Signed-off-by James Bottomley <[email protected]>

---
 drivers/scsi/scsi_lib.c     |    8 +++++---
 include/linux/scatterlist.h |    5 +++--
 lib/scatterlist.c           |   41 +++++++++++++++++++++++++++--------------
 3 files changed, 35 insertions(+), 19 deletions(-)

drivers/scsi/scsi_lib.c +5 -3

index 3c681de..e0f40e6 100644
@@ -773,16 +773,18 @@ static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
 
 	BUG_ON(!nents);
 
-	ret = __sg_alloc_table(&sdb->table, nents, gfp_mask, scsi_sg_alloc);
+	ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
+			       gfp_mask, scsi_sg_alloc);
 	if (unlikely(ret))
-		__sg_free_table(&sdb->table, scsi_sg_free);
+		__sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
+				scsi_sg_free);
 
 	return ret;
 }
 
 static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
 {
-	__sg_free_table(&sdb->table, scsi_sg_free);
+	__sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
 }
 
 /*

include/linux/scatterlist.h +3 -2

index e9cb103..a3d567a 100644
@@ -207,9 +207,10 @@ void sg_init_one(struct scatterlist *, const void *, unsigned int);
 typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t);
 typedef void (sg_free_fn)(struct scatterlist *, unsigned int);
 
-void __sg_free_table(struct sg_table *, sg_free_fn *);
+void __sg_free_table(struct sg_table *, unsigned int, sg_free_fn *);
 void sg_free_table(struct sg_table *);
-int __sg_alloc_table(struct sg_table *, unsigned int, gfp_t, sg_alloc_fn *);
+int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, gfp_t,
+		     sg_alloc_fn *);
 int sg_alloc_table(struct sg_table *, unsigned int, gfp_t);
 
 /*

lib/scatterlist.c +27 ~~-14~~

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