| Message ID | 1314043438-21590-1-git-send-email-robotboy@chromium.org |
|---|---|
| State | Superseded |
| Headers | show |
Ooops, expect a follow up without that last minute addition of a C++ style comment about ENOMEM, sorry... -Anton On Mon, Aug 22, 2011 at 1:03 PM, Anton Staaf <robotboy@chromium.org> wrote: > Currently, if a device read request is done that does not begin or end > on a sector boundary a stack allocated bounce buffer is used to perform > the read, and then just the part of the sector that is needed is copied > into the users buffer. This stack allocation can mean that the bounce > buffer will not be aligned to the dcache line size. This is a problem > when caches are enabled because unaligned cache invalidates are not > safe. > > This patch allocates a cache line size aligned sector sized bounce > buffer the first time that ext2fs_devread is called. > > Signed-off-by: Anton Staaf <robotboy@chromium.org> > Cc: Lukasz Majewski <l.majewski@samsung.com> > Cc: Mike Frysinger <vapier@gentoo.org> > Cc: Dave Liu <r63238@freescale.com> > Cc: Andy Fleming <afleming@gmail.com> > Cc: Albert ARIBAUD <albert.u.boot@aribaud.net> > --- > > This patch depends on Lukasz Majewski's dcache line size patch sent to the > list in: http://patchwork.ozlabs.org/patch/110501/ > > fs/ext2/dev.c | 9 ++++++++- > 1 files changed, 8 insertions(+), 1 deletions(-) > > diff --git a/fs/ext2/dev.c b/fs/ext2/dev.c > index 78851d0..4b2aeef 100644 > --- a/fs/ext2/dev.c > +++ b/fs/ext2/dev.c > @@ -26,6 +26,7 @@ > > #include <common.h> > #include <config.h> > +#include <malloc.h> > #include <ext2fs.h> > > static block_dev_desc_t *ext2fs_block_dev_desc; > @@ -52,9 +53,15 @@ int ext2fs_set_blk_dev(block_dev_desc_t *rbdd, int part) > > int ext2fs_devread(int sector, int byte_offset, int byte_len, char *buf) > { > - char sec_buf[SECTOR_SIZE]; > + static char *sec_buf; > unsigned sectors; > > + if (sec_buf == NULL) > + sec_buf = memalign(get_dcache_line_size(), SECTOR_SIZE); > + > + if (sec_buf == NULL) > + return 0; //-ENOMEM > + > /* > * Check partition boundaries > */ > -- > 1.7.3.1 > >
diff --git a/fs/ext2/dev.c b/fs/ext2/dev.c index 78851d0..4b2aeef 100644 --- a/fs/ext2/dev.c +++ b/fs/ext2/dev.c @@ -26,6 +26,7 @@ #include <common.h> #include <config.h> +#include <malloc.h> #include <ext2fs.h> static block_dev_desc_t *ext2fs_block_dev_desc; @@ -52,9 +53,15 @@ int ext2fs_set_blk_dev(block_dev_desc_t *rbdd, int part) int ext2fs_devread(int sector, int byte_offset, int byte_len, char *buf) { - char sec_buf[SECTOR_SIZE]; + static char *sec_buf; unsigned sectors; + if (sec_buf == NULL) + sec_buf = memalign(get_dcache_line_size(), SECTOR_SIZE); + + if (sec_buf == NULL) + return 0; //-ENOMEM + /* * Check partition boundaries */
Currently, if a device read request is done that does not begin or end on a sector boundary a stack allocated bounce buffer is used to perform the read, and then just the part of the sector that is needed is copied into the users buffer. This stack allocation can mean that the bounce buffer will not be aligned to the dcache line size. This is a problem when caches are enabled because unaligned cache invalidates are not safe. This patch allocates a cache line size aligned sector sized bounce buffer the first time that ext2fs_devread is called. Signed-off-by: Anton Staaf <robotboy@chromium.org> Cc: Lukasz Majewski <l.majewski@samsung.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Dave Liu <r63238@freescale.com> Cc: Andy Fleming <afleming@gmail.com> Cc: Albert ARIBAUD <albert.u.boot@aribaud.net> --- This patch depends on Lukasz Majewski's dcache line size patch sent to the list in: http://patchwork.ozlabs.org/patch/110501/ fs/ext2/dev.c | 9 ++++++++- 1 files changed, 8 insertions(+), 1 deletions(-)