From: Andrey Smirnov <andrew.smirnov@gmail.com>
To: barebox@lists.infradead.org
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Subject: [PATCH v2 14/19] fs: Avoid division in mem_copy()
Date: Mon, 28 Jan 2019 22:55:44 -0800 [thread overview]
Message-ID: <20190129065549.29161-15-andrew.smirnov@gmail.com> (raw)
In-Reply-To: <20190129065549.29161-1-andrew.smirnov@gmail.com>
Instead of dividing count by rwsize, use ALIGN_DOWN() and change the
loop to decrement by "rwsize" bytes.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
fs/devfs-core.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/devfs-core.c b/fs/devfs-core.c
index 37c4bd0ad..8d5ff71d6 100644
--- a/fs/devfs-core.c
+++ b/fs/devfs-core.c
@@ -548,9 +548,9 @@ static ssize_t mem_copy(struct device_d *dev, void *dst, const void *src,
rwsize = rwsize >> O_RWSIZE_SHIFT;
- count /= rwsize;
+ count = ALIGN_DOWN(count, rwsize);
- while (count-- > 0) {
+ while (count) {
switch (rwsize) {
case 1:
*((u8 *)dst) = *((u8 *)src);
@@ -567,6 +567,7 @@ static ssize_t mem_copy(struct device_d *dev, void *dst, const void *src,
}
dst += rwsize;
src += rwsize;
+ count -= rwsize;
}
out:
return size;
--
2.20.1
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next prev parent reply other threads:[~2019-01-29 6:56 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-29 6:55 [PATCH v2 00/19] 32-bit lseek and /dev/mem fixes/improvements Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 01/19] commands: Move mem_parse_options() to lib/misc.c Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 02/19] commands: Get rid of mem_rw_buf Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 03/19] commands: Move /dev/mem driver to drivers/misc Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 04/19] nvmem: Do not use DEVFS_IS_CHARACTER_DEV Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 05/19] common: firmware: Don't use FILE_SIZE_STREAM directly Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 06/19] devfs: Fix incorrect error check for cdev->ops->lseek() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 07/19] fs: Update FILE position in lseek() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 08/19] fs: Drop trivial .lseek() implementaitons in FS drivers Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 09/19] devfs: Drop dev_lseek_default() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 10/19] fs: devfs: Change .lseek callbacks to return 'int' Andrey Smirnov
2019-02-04 14:32 ` Sascha Hauer
2019-01-29 6:55 ` [PATCH v2 11/19] fs: Do not use IS_ERR_VALUE() to validate offset in lseek() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 12/19] fs: Simplify new position calculation " Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 13/19] fs: Share code between mem_write()/mem_read() Andrey Smirnov
2019-01-29 6:55 ` Andrey Smirnov [this message]
2019-01-29 6:55 ` [PATCH v2 15/19] fs: Report actual data processed by mem_copy() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 16/19] fs: Introduce mem_read_nofail() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 17/19] commands: md: Do not use memmap() Andrey Smirnov
2019-02-04 13:57 ` Sascha Hauer
2019-02-04 19:35 ` Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 18/19] drivers: mem: Create file to access second half of 64-bit memory Andrey Smirnov
2019-01-29 8:48 ` Sascha Hauer
2019-01-29 20:40 ` Andrey Smirnov
2019-01-29 21:09 ` Sam Ravnborg
2019-01-31 10:54 ` Peter Mamonov
2019-01-31 12:50 ` Peter Mamonov
2019-02-01 7:47 ` Sascha Hauer
2019-02-01 10:25 ` Peter Mamonov
2019-02-02 1:07 ` Andrey Smirnov
2019-02-02 0:35 ` Andrey Smirnov
2019-02-04 7:40 ` Sascha Hauer
2019-01-31 20:17 ` Andrey Smirnov
2019-02-01 10:14 ` Peter Mamonov
2019-01-29 6:55 ` [PATCH v2 19/19] libfile: Fix incorrect lseek check in open_and_lseek() Andrey Smirnov
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