diff options
author | Christoph Hellwig <hch@infradead.org> | 2007-10-11 21:12:39 -0400 |
---|---|---|
committer | Lachlan McIlroy <lachlan@redback.melbourne.sgi.com> | 2008-02-07 02:12:07 -0500 |
commit | c40ea74101ab75a8f320d057e7cf4b772b090110 (patch) | |
tree | 047b725cf7347e4111b65edd532cf9b1ee8010d1 /fs/xfs | |
parent | 0771fb4515229821b7d74865b87a430de9fc1113 (diff) |
[XFS] kill superflous buffer locking
There is no need to lock any page in xfs_buf.c because we operate on our
own address_space and all locking is covered by the buffer semaphore. If
we ever switch back to main blockdeive address_space as suggested e.g. for
fsblock with a similar scheme the locking will have to be totally revised
anyway because the current scheme is neither correct nor coherent with
itself.
SGI-PV: 971186
SGI-Modid: xfs-linux-melb:xfs-kern:29845a
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
Diffstat (limited to 'fs/xfs')
-rw-r--r-- | fs/xfs/linux-2.6/xfs_buf.c | 53 | ||||
-rw-r--r-- | fs/xfs/linux-2.6/xfs_buf.h | 1 |
2 files changed, 5 insertions, 49 deletions
diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c index 522cfaa70258..a7c7cb27fa5a 100644 --- a/fs/xfs/linux-2.6/xfs_buf.c +++ b/fs/xfs/linux-2.6/xfs_buf.c | |||
@@ -409,6 +409,7 @@ _xfs_buf_lookup_pages( | |||
409 | congestion_wait(WRITE, HZ/50); | 409 | congestion_wait(WRITE, HZ/50); |
410 | goto retry; | 410 | goto retry; |
411 | } | 411 | } |
412 | unlock_page(page); | ||
412 | 413 | ||
413 | XFS_STATS_INC(xb_page_found); | 414 | XFS_STATS_INC(xb_page_found); |
414 | 415 | ||
@@ -418,10 +419,7 @@ _xfs_buf_lookup_pages( | |||
418 | ASSERT(!PagePrivate(page)); | 419 | ASSERT(!PagePrivate(page)); |
419 | if (!PageUptodate(page)) { | 420 | if (!PageUptodate(page)) { |
420 | page_count--; | 421 | page_count--; |
421 | if (blocksize >= PAGE_CACHE_SIZE) { | 422 | if (blocksize < PAGE_CACHE_SIZE && !PagePrivate(page)) { |
422 | if (flags & XBF_READ) | ||
423 | bp->b_locked = 1; | ||
424 | } else if (!PagePrivate(page)) { | ||
425 | if (test_page_region(page, offset, nbytes)) | 423 | if (test_page_region(page, offset, nbytes)) |
426 | page_count++; | 424 | page_count++; |
427 | } | 425 | } |
@@ -431,11 +429,6 @@ _xfs_buf_lookup_pages( | |||
431 | offset = 0; | 429 | offset = 0; |
432 | } | 430 | } |
433 | 431 | ||
434 | if (!bp->b_locked) { | ||
435 | for (i = 0; i < bp->b_page_count; i++) | ||
436 | unlock_page(bp->b_pages[i]); | ||
437 | } | ||
438 | |||
439 | if (page_count == bp->b_page_count) | 432 | if (page_count == bp->b_page_count) |
440 | bp->b_flags |= XBF_DONE; | 433 | bp->b_flags |= XBF_DONE; |
441 | 434 | ||
@@ -752,7 +745,6 @@ xfs_buf_associate_memory( | |||
752 | bp->b_pages[i] = mem_to_page((void *)pageaddr); | 745 | bp->b_pages[i] = mem_to_page((void *)pageaddr); |
753 | pageaddr += PAGE_CACHE_SIZE; | 746 | pageaddr += PAGE_CACHE_SIZE; |
754 | } | 747 | } |
755 | bp->b_locked = 0; | ||
756 | 748 | ||
757 | bp->b_count_desired = len; | 749 | bp->b_count_desired = len; |
758 | bp->b_buffer_length = buflen; | 750 | bp->b_buffer_length = buflen; |
@@ -1099,25 +1091,13 @@ xfs_buf_iostart( | |||
1099 | return status; | 1091 | return status; |
1100 | } | 1092 | } |
1101 | 1093 | ||
1102 | STATIC_INLINE int | ||
1103 | _xfs_buf_iolocked( | ||
1104 | xfs_buf_t *bp) | ||
1105 | { | ||
1106 | ASSERT(bp->b_flags & (XBF_READ | XBF_WRITE)); | ||
1107 | if (bp->b_flags & XBF_READ) | ||
1108 | return bp->b_locked; | ||
1109 | return 0; | ||
1110 | } | ||
1111 | |||
1112 | STATIC_INLINE void | 1094 | STATIC_INLINE void |
1113 | _xfs_buf_ioend( | 1095 | _xfs_buf_ioend( |
1114 | xfs_buf_t *bp, | 1096 | xfs_buf_t *bp, |
1115 | int schedule) | 1097 | int schedule) |
1116 | { | 1098 | { |
1117 | if (atomic_dec_and_test(&bp->b_io_remaining) == 1) { | 1099 | if (atomic_dec_and_test(&bp->b_io_remaining) == 1) |
1118 | bp->b_locked = 0; | ||
1119 | xfs_buf_ioend(bp, schedule); | 1100 | xfs_buf_ioend(bp, schedule); |
1120 | } | ||
1121 | } | 1101 | } |
1122 | 1102 | ||
1123 | STATIC void | 1103 | STATIC void |
@@ -1148,10 +1128,6 @@ xfs_buf_bio_end_io( | |||
1148 | 1128 | ||
1149 | if (--bvec >= bio->bi_io_vec) | 1129 | if (--bvec >= bio->bi_io_vec) |
1150 | prefetchw(&bvec->bv_page->flags); | 1130 | prefetchw(&bvec->bv_page->flags); |
1151 | |||
1152 | if (_xfs_buf_iolocked(bp)) { | ||
1153 | unlock_page(page); | ||
1154 | } | ||
1155 | } while (bvec >= bio->bi_io_vec); | 1131 | } while (bvec >= bio->bi_io_vec); |
1156 | 1132 | ||
1157 | _xfs_buf_ioend(bp, 1); | 1133 | _xfs_buf_ioend(bp, 1); |
@@ -1162,13 +1138,12 @@ STATIC void | |||
1162 | _xfs_buf_ioapply( | 1138 | _xfs_buf_ioapply( |
1163 | xfs_buf_t *bp) | 1139 | xfs_buf_t *bp) |
1164 | { | 1140 | { |
1165 | int i, rw, map_i, total_nr_pages, nr_pages; | 1141 | int rw, map_i, total_nr_pages, nr_pages; |
1166 | struct bio *bio; | 1142 | struct bio *bio; |
1167 | int offset = bp->b_offset; | 1143 | int offset = bp->b_offset; |
1168 | int size = bp->b_count_desired; | 1144 | int size = bp->b_count_desired; |
1169 | sector_t sector = bp->b_bn; | 1145 | sector_t sector = bp->b_bn; |
1170 | unsigned int blocksize = bp->b_target->bt_bsize; | 1146 | unsigned int blocksize = bp->b_target->bt_bsize; |
1171 | int locking = _xfs_buf_iolocked(bp); | ||
1172 | 1147 | ||
1173 | total_nr_pages = bp->b_page_count; | 1148 | total_nr_pages = bp->b_page_count; |
1174 | map_i = 0; | 1149 | map_i = 0; |
@@ -1191,7 +1166,7 @@ _xfs_buf_ioapply( | |||
1191 | * filesystem block size is not smaller than the page size. | 1166 | * filesystem block size is not smaller than the page size. |
1192 | */ | 1167 | */ |
1193 | if ((bp->b_buffer_length < PAGE_CACHE_SIZE) && | 1168 | if ((bp->b_buffer_length < PAGE_CACHE_SIZE) && |
1194 | (bp->b_flags & XBF_READ) && locking && | 1169 | (bp->b_flags & XBF_READ) && |
1195 | (blocksize >= PAGE_CACHE_SIZE)) { | 1170 | (blocksize >= PAGE_CACHE_SIZE)) { |
1196 | bio = bio_alloc(GFP_NOIO, 1); | 1171 | bio = bio_alloc(GFP_NOIO, 1); |
1197 | 1172 | ||
@@ -1208,24 +1183,6 @@ _xfs_buf_ioapply( | |||
1208 | goto submit_io; | 1183 | goto submit_io; |
1209 | } | 1184 | } |
1210 | 1185 | ||
1211 | /* Lock down the pages which we need to for the request */ | ||
1212 | if (locking && (bp->b_flags & XBF_WRITE) && (bp->b_locked == 0)) { | ||
1213 | for (i = 0; size; i++) { | ||
1214 | int nbytes = PAGE_CACHE_SIZE - offset; | ||
1215 | struct page *page = bp->b_pages[i]; | ||
1216 | |||
1217 | if (nbytes > size) | ||
1218 | nbytes = size; | ||
1219 | |||
1220 | lock_page(page); | ||
1221 | |||
1222 | size -= nbytes; | ||
1223 | offset = 0; | ||
1224 | } | ||
1225 | offset = bp->b_offset; | ||
1226 | size = bp->b_count_desired; | ||
1227 | } | ||
1228 | |||
1229 | next_chunk: | 1186 | next_chunk: |
1230 | atomic_inc(&bp->b_io_remaining); | 1187 | atomic_inc(&bp->b_io_remaining); |
1231 | nr_pages = BIO_MAX_SECTORS >> (PAGE_SHIFT - BBSHIFT); | 1188 | nr_pages = BIO_MAX_SECTORS >> (PAGE_SHIFT - BBSHIFT); |
diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h index b5908a34b15d..a3d207de48b8 100644 --- a/fs/xfs/linux-2.6/xfs_buf.h +++ b/fs/xfs/linux-2.6/xfs_buf.h | |||
@@ -143,7 +143,6 @@ typedef struct xfs_buf { | |||
143 | void *b_fspriv2; | 143 | void *b_fspriv2; |
144 | void *b_fspriv3; | 144 | void *b_fspriv3; |
145 | unsigned short b_error; /* error code on I/O */ | 145 | unsigned short b_error; /* error code on I/O */ |
146 | unsigned short b_locked; /* page array is locked */ | ||
147 | unsigned int b_page_count; /* size of page array */ | 146 | unsigned int b_page_count; /* size of page array */ |
148 | unsigned int b_offset; /* page offset in first page */ | 147 | unsigned int b_offset; /* page offset in first page */ |
149 | struct page **b_pages; /* array of page pointers */ | 148 | struct page **b_pages; /* array of page pointers */ |