104 lines
3.7 KiB
Diff
104 lines
3.7 KiB
Diff
From 40eeced3fb25780be27799b2a72a2264ef64163b Mon Sep 17 00:00:00 2001
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From: Vladimir 'phcoder' Serbinenko <phcoder@gmail.com>
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Date: Sat, 5 Jan 2013 18:37:34 +0100
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Subject: [PATCH 088/482] * grub-core/fs/ext2.c (grub_ext2_read_block):
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Use shifts rather than divisions.
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---
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ChangeLog | 5 +++++
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grub-core/fs/ext2.c | 30 ++++++++++++++++--------------
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2 files changed, 21 insertions(+), 14 deletions(-)
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diff --git a/ChangeLog b/ChangeLog
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index 88fd763..af29161 100644
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--- a/ChangeLog
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+++ b/ChangeLog
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@@ -1,5 +1,10 @@
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2013-01-05 Vladimir Serbinenko <phcoder@gmail.com>
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+ * grub-core/fs/ext2.c (grub_ext2_read_block): Use shifts rather than
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+ divisions.
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+
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+2013-01-05 Vladimir Serbinenko <phcoder@gmail.com>
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+
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* grub-core/fs/ntfs.c: Eliminate useless divisions in favor of shifts.
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* grub-core/fs/ntfscomp.c: Likewise.
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* include/grub/ntfs.h (grub_ntfs_data): Replace spc with log_spc.
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diff --git a/grub-core/fs/ext2.c b/grub-core/fs/ext2.c
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index bd1ab24..cf2e2f4 100644
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--- a/grub-core/fs/ext2.c
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+++ b/grub-core/fs/ext2.c
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@@ -454,11 +454,12 @@ grub_ext2_read_block (grub_fshelp_node_t node, grub_disk_addr_t fileblock)
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blknr = grub_le_to_cpu32 (indir[fileblock - INDIRECT_BLOCKS]);
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}
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/* Double indirect. */
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- else if (fileblock < INDIRECT_BLOCKS + blksz / 4 * (blksz / 4 + 1))
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+ else if (fileblock < INDIRECT_BLOCKS
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+ + blksz / 4 * ((grub_disk_addr_t) blksz / 4 + 1))
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{
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- unsigned int perblock = blksz / 4;
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- unsigned int rblock = fileblock - (INDIRECT_BLOCKS
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- + blksz / 4);
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+ int log_perblock = log2_blksz + 9 - 2;
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+ grub_disk_addr_t rblock = fileblock - (INDIRECT_BLOCKS
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+ + blksz / 4);
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grub_uint32_t indir[blksz / 4];
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if (grub_disk_read (data->disk,
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@@ -470,21 +471,22 @@ grub_ext2_read_block (grub_fshelp_node_t node, grub_disk_addr_t fileblock)
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if (grub_disk_read (data->disk,
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((grub_disk_addr_t)
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- grub_le_to_cpu32 (indir[rblock / perblock]))
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+ grub_le_to_cpu32 (indir[rblock >> log_perblock]))
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<< log2_blksz,
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0, blksz, indir))
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return grub_errno;
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- blknr = grub_le_to_cpu32 (indir[rblock % perblock]);
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+ blknr = grub_le_to_cpu32 (indir[rblock & ((1 << log_perblock) - 1)]);
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}
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/* triple indirect. */
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- else if (fileblock < INDIRECT_BLOCKS + blksz / 4 * (blksz / 4 + 1)
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- + (blksz / 4) * (blksz / 4) * (blksz / 4 + 1))
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+ else if (fileblock < INDIRECT_BLOCKS + blksz / 4 * ((grub_disk_addr_t) blksz / 4 + 1)
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+ + ((grub_disk_addr_t) blksz / 4) * ((grub_disk_addr_t) blksz / 4)
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+ * ((grub_disk_addr_t) blksz / 4 + 1))
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{
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- unsigned int perblock = blksz / 4;
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- unsigned int rblock = fileblock - (INDIRECT_BLOCKS + blksz / 4
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- * (blksz / 4 + 1));
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+ int log_perblock = log2_blksz + 9 - 2;
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+ grub_disk_addr_t rblock = fileblock - (INDIRECT_BLOCKS + blksz / 4
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+ * (blksz / 4 + 1));
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grub_uint32_t indir[blksz / 4];
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if (grub_disk_read (data->disk,
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@@ -496,19 +498,19 @@ grub_ext2_read_block (grub_fshelp_node_t node, grub_disk_addr_t fileblock)
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if (grub_disk_read (data->disk,
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((grub_disk_addr_t)
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- grub_le_to_cpu32 (indir[(rblock / perblock) / perblock]))
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+ grub_le_to_cpu32 (indir[(rblock >> log_perblock) >> log_perblock]))
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<< log2_blksz,
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0, blksz, indir))
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return grub_errno;
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if (grub_disk_read (data->disk,
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((grub_disk_addr_t)
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- grub_le_to_cpu32 (indir[(rblock / perblock) % perblock]))
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+ grub_le_to_cpu32 (indir[(rblock >> log_perblock) & ((1 << log_perblock) - 1)]))
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<< log2_blksz,
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0, blksz, indir))
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return grub_errno;
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- blknr = grub_le_to_cpu32 (indir[rblock % perblock]);
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+ blknr = grub_le_to_cpu32 (indir[rblock & ((1 << log_perblock) - 1)]);
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}
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else
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{
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--
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1.8.2.1
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