On Tue, 15 Jul 2008 22:27:51 +0900
Yoichi Yuasa <yoichi_yuasa@xxxxxxxxxxxxxx> wrote:
> I update cobalt_lcdfb driver.
>
> v3
> - fix read/write count boundary check.
> - add <include/uaccess.h>.
> - fix MODULE_AUTHOR.
>
> v2
> - add dpends MIPS_COBALT in Kconfig.
> - add handling of signal_pending().
> - check overflow of read/write count.
>
> v1
> - first release.
This driver has been merged into the subsystem tree for a long time and
has been reviewed and has been perhaps tested by others. Sending a
complete new version of the entire thing is really quite an unfriendly
act. It basically invalidates all the review and test work which
everyone else has done.
This is why I will almost always turn replacement patches into
incremental patches - so I can see what changed. But that's only good
for me. Everyone else who is reading your new version won't bother
doing that.
So I generated the incremental patch and:
- The driver I have already includes linux/uaccess.h, so that change
was unneeded.
- The driver I have has already fixed the reject in
drivers/video/Makefile, so I get to fix it again, ho hum.
Here's what I ended up committing:
drivers/video/Kconfig | 2 +-
drivers/video/cobalt_lcdfb.c | 24 ++++++++++++++++++------
2 files changed, 19 insertions(+), 7 deletions(-)
diff -puN drivers/video/Kconfig~add-new-cobalt-lcd-framebuffer-driver drivers/video/Kconfig
--- a/drivers/video/Kconfig~add-new-cobalt-lcd-framebuffer-driver
+++ a/drivers/video/Kconfig
@@ -1989,7 +1989,7 @@ config FB_AM200EPD
config FB_COBALT
tristate "Cobalt server LCD frame buffer support"
- depends on FB
+ depends on FB && MIPS_COBALT
config FB_VIRTUAL
tristate "Virtual Frame Buffer support (ONLY FOR TESTING!)"
diff -puN drivers/video/Makefile~add-new-cobalt-lcd-framebuffer-driver drivers/video/Makefile
diff -puN drivers/video/cobalt_lcdfb.c~add-new-cobalt-lcd-framebuffer-driver drivers/video/cobalt_lcdfb.c
--- a/drivers/video/cobalt_lcdfb.c~add-new-cobalt-lcd-framebuffer-driver
+++ a/drivers/video/cobalt_lcdfb.c
@@ -137,13 +137,16 @@ static ssize_t cobalt_lcdfb_read(struct
{
char src[LCD_CHARS_MAX];
unsigned long pos;
- int len, retval;
+ int len, retval = 0;
pos = *ppos;
- if (pos >= LCD_CHARS_MAX)
+ if (pos >= LCD_CHARS_MAX || count == 0)
return 0;
- if (pos + count >= LCD_CHARS_MAX)
+ if (count > LCD_CHARS_MAX)
+ count = LCD_CHARS_MAX;
+
+ if (pos + count > LCD_CHARS_MAX)
count = LCD_CHARS_MAX - pos;
for (len = 0; len < count; len++) {
@@ -164,6 +167,9 @@ static ssize_t cobalt_lcdfb_read(struct
pos++;
}
+ if (retval < 0 && signal_pending(current))
+ return -ERESTARTSYS;
+
if (copy_to_user(buf, src, len))
return -EFAULT;
@@ -177,13 +183,16 @@ static ssize_t cobalt_lcdfb_write(struct
{
char dst[LCD_CHARS_MAX];
unsigned long pos;
- int len, retval;
+ int len, retval = 0;
pos = *ppos;
- if (pos >= LCD_CHARS_MAX)
+ if (pos >= LCD_CHARS_MAX || count == 0)
return 0;
- if (pos + count >= LCD_CHARS_MAX)
+ if (count > LCD_CHARS_MAX)
+ count = LCD_CHARS_MAX;
+
+ if (pos + count > LCD_CHARS_MAX)
count = LCD_CHARS_MAX - pos;
if (copy_from_user(dst, buf, count))
@@ -207,6 +216,9 @@ static ssize_t cobalt_lcdfb_write(struct
pos++;
}
+ if (retval < 0 && signal_pending(current))
+ return -ERESTARTSYS;
+
*ppos += len;
return len;
_
and I'm a bit uncertain about it.
- the test for (count > LCD_CHARS_MAX) appear to be unneeded, given
the follwing test for (pos + count > LCD_CHARS_MAX).
Or perhaps it is an obscure test for very large tests of `count',
which would cause overflows in `count+pos'? Can it all be simplified?
- Do we need to test for `count == 0'? I have a feeling that this
case is handled at the higher levels of read(), but I cannot find
that piece of code at present. Perhaps I dreamed it.
