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| author | Joel Becker <joel.becker@oracle.com> | 2007-06-22 13:07:02 -0700 |
|---|---|---|
| committer | Mark Fasheh <mark.fasheh@oracle.com> | 2007-07-10 16:52:22 -0700 |
| commit | b23cdde4c6240d70bb3d2e3c4046b60d6f6c8451 (patch) | |
| tree | ed1965f424197194def20aa1ed10867f9fac6836 /fs/configfs | |
| parent | 4c75f7416f51b0c6855952467a5db04f9c598f09 (diff) | |
| download | lwn-b23cdde4c6240d70bb3d2e3c4046b60d6f6c8451.tar.gz lwn-b23cdde4c6240d70bb3d2e3c4046b60d6f6c8451.zip | |
configfs: consistent attribute size
The attribute store/show code currently limits attributes at PAGE_SIZE.
This code comes from sysfs, where it still works that way.
However, PAGE_SIZE is not constant. A 16k attribute string works on
ia64 but not on x86. Really a subsystem shouldn't allow different
attribute sizes based on platform.
As such, limit all simple attributes to 4k. This works on all
platforms, and is consistent with all current code.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Diffstat (limited to 'fs/configfs')
| -rw-r--r-- | fs/configfs/file.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/fs/configfs/file.c b/fs/configfs/file.c index 3527c7c6def8..0f4b65e85245 100644 --- a/fs/configfs/file.c +++ b/fs/configfs/file.c @@ -33,6 +33,13 @@ #include <linux/configfs.h> #include "configfs_internal.h" +/* + * A simple attribute can only be 4096 characters. Why 4k? Because the + * original code limited it to PAGE_SIZE. That's a bad idea, though, + * because an attribute of 16k on ia64 won't work on x86. So we limit to + * 4k, our minimum common page size. + */ +#define SIMPLE_ATTR_SIZE 4096 struct configfs_buffer { size_t count; @@ -69,7 +76,7 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf count = ops->show_attribute(item,attr,buffer->page); buffer->needs_read_fill = 0; - BUG_ON(count > (ssize_t)PAGE_SIZE); + BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE); if (count >= 0) buffer->count = count; else @@ -137,8 +144,8 @@ fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size if (!buffer->page) return -ENOMEM; - if (count >= PAGE_SIZE) - count = PAGE_SIZE - 1; + if (count >= SIMPLE_ATTR_SIZE) + count = SIMPLE_ATTR_SIZE - 1; error = copy_from_user(buffer->page,buf,count); buffer->needs_read_fill = 1; /* if buf is assumed to contain a string, terminate it by \0, |