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authorBjorn Helgaas <bhelgaas@google.com>2012-09-13 08:41:01 -0600
committerBjorn Helgaas <bhelgaas@google.com>2012-09-13 08:41:01 -0600
commit78890b5989d96ddce989cde929c45ceeded0fcaf (patch)
tree4e2da81fc7c97f11aee174b1eedac110c9a68b3a /block/blk-merge.c
parent1959ec5f82acbdf91425b41600f119ebecb5f6a8 (diff)
parent55d512e245bc7699a8800e23df1a24195dd08217 (diff)
Merge commit 'v3.6-rc5' into next
* commit 'v3.6-rc5': (1098 commits) Linux 3.6-rc5 HID: tpkbd: work even if the new Lenovo Keyboard driver is not configured Remove user-triggerable BUG from mpol_to_str xen/pciback: Fix proper FLR steps. uml: fix compile error in deliver_alarm() dj: memory scribble in logi_dj Fix order of arguments to compat_put_time[spec|val] xen: Use correct masking in xen_swiotlb_alloc_coherent. xen: fix logical error in tlb flushing xen/p2m: Fix one-off error in checking the P2M tree directory. powerpc: Don't use __put_user() in patch_instruction powerpc: Make sure IPI handlers see data written by IPI senders powerpc: Restore correct DSCR in context switch powerpc: Fix DSCR inheritance in copy_thread() powerpc: Keep thread.dscr and thread.dscr_inherit in sync powerpc: Update DSCR on all CPUs when writing sysfs dscr_default powerpc/powernv: Always go into nap mode when CPU is offline powerpc: Give hypervisor decrementer interrupts their own handler powerpc/vphn: Fix arch_update_cpu_topology() return value ARM: gemini: fix the gemini build ... Conflicts: drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c drivers/rapidio/devices/tsi721.c
Diffstat (limited to 'block/blk-merge.c')
-rw-r--r--block/blk-merge.c117
1 files changed, 82 insertions, 35 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 160035f5488..e76279e4116 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -110,6 +110,49 @@ static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
return 0;
}
+static void
+__blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec,
+ struct scatterlist *sglist, struct bio_vec **bvprv,
+ struct scatterlist **sg, int *nsegs, int *cluster)
+{
+
+ int nbytes = bvec->bv_len;
+
+ if (*bvprv && *cluster) {
+ if ((*sg)->length + nbytes > queue_max_segment_size(q))
+ goto new_segment;
+
+ if (!BIOVEC_PHYS_MERGEABLE(*bvprv, bvec))
+ goto new_segment;
+ if (!BIOVEC_SEG_BOUNDARY(q, *bvprv, bvec))
+ goto new_segment;
+
+ (*sg)->length += nbytes;
+ } else {
+new_segment:
+ if (!*sg)
+ *sg = sglist;
+ else {
+ /*
+ * If the driver previously mapped a shorter
+ * list, we could see a termination bit
+ * prematurely unless it fully inits the sg
+ * table on each mapping. We KNOW that there
+ * must be more entries here or the driver
+ * would be buggy, so force clear the
+ * termination bit to avoid doing a full
+ * sg_init_table() in drivers for each command.
+ */
+ (*sg)->page_link &= ~0x02;
+ *sg = sg_next(*sg);
+ }
+
+ sg_set_page(*sg, bvec->bv_page, nbytes, bvec->bv_offset);
+ (*nsegs)++;
+ }
+ *bvprv = bvec;
+}
+
/*
* map a request to scatterlist, return number of sg entries setup. Caller
* must make sure sg can hold rq->nr_phys_segments entries
@@ -131,41 +174,8 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
bvprv = NULL;
sg = NULL;
rq_for_each_segment(bvec, rq, iter) {
- int nbytes = bvec->bv_len;
-
- if (bvprv && cluster) {
- if (sg->length + nbytes > queue_max_segment_size(q))
- goto new_segment;
-
- if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec))
- goto new_segment;
- if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec))
- goto new_segment;
-
- sg->length += nbytes;
- } else {
-new_segment:
- if (!sg)
- sg = sglist;
- else {
- /*
- * If the driver previously mapped a shorter
- * list, we could see a termination bit
- * prematurely unless it fully inits the sg
- * table on each mapping. We KNOW that there
- * must be more entries here or the driver
- * would be buggy, so force clear the
- * termination bit to avoid doing a full
- * sg_init_table() in drivers for each command.
- */
- sg->page_link &= ~0x02;
- sg = sg_next(sg);
- }
-
- sg_set_page(sg, bvec->bv_page, nbytes, bvec->bv_offset);
- nsegs++;
- }
- bvprv = bvec;
+ __blk_segment_map_sg(q, bvec, sglist, &bvprv, &sg,
+ &nsegs, &cluster);
} /* segments in rq */
@@ -199,6 +209,43 @@ new_segment:
}
EXPORT_SYMBOL(blk_rq_map_sg);
+/**
+ * blk_bio_map_sg - map a bio to a scatterlist
+ * @q: request_queue in question
+ * @bio: bio being mapped
+ * @sglist: scatterlist being mapped
+ *
+ * Note:
+ * Caller must make sure sg can hold bio->bi_phys_segments entries
+ *
+ * Will return the number of sg entries setup
+ */
+int blk_bio_map_sg(struct request_queue *q, struct bio *bio,
+ struct scatterlist *sglist)
+{
+ struct bio_vec *bvec, *bvprv;
+ struct scatterlist *sg;
+ int nsegs, cluster;
+ unsigned long i;
+
+ nsegs = 0;
+ cluster = blk_queue_cluster(q);
+
+ bvprv = NULL;
+ sg = NULL;
+ bio_for_each_segment(bvec, bio, i) {
+ __blk_segment_map_sg(q, bvec, sglist, &bvprv, &sg,
+ &nsegs, &cluster);
+ } /* segments in bio */
+
+ if (sg)
+ sg_mark_end(sg);
+
+ BUG_ON(bio->bi_phys_segments && nsegs > bio->bi_phys_segments);
+ return nsegs;
+}
+EXPORT_SYMBOL(blk_bio_map_sg);
+
static inline int ll_new_hw_segment(struct request_queue *q,
struct request *req,
struct bio *bio)