On 05/18/2016 04:16 PM, Marek Vasut wrote: > The simple_write_to_buffer() already increments the @ppos on success, > see fs/libfs.c simple_write_to_buffer() comment: > > " > On success, the number of bytes written is returned and the offset @ppos > advanced by this number, or negative value is returned on error. > " > > If the configfs_write_bin_file() is invoked with @count smaller than the > total length of the written binary file, it will be invoked multiple times. > Since configfs_write_bin_file() increments @ppos on success, after calling > simple_write_to_buffer(), the @ppos is incremented twice. > > Subsequent invocation of configfs_write_bin_file() will result in the next > piece of data being written to the offset twice as long as the length of > the previous write, thus creating buffer with "holes" in it. > > The simple testcase using DTO follows: > $ mkdir /sys/kernel/config/device-tree/overlays/1 > $ dd bs=1 if=foo.dtbo of=/sys/kernel/config/device-tree/overlays/1/dtbo > Without this patch, the testcase will result in twice as big buffer in the > kernel, which is then passed to the cfs_overlay_item_dtbo_write() . > > Signed-off-by: Marek Vasut <marex@xxxxxxx> > Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> > Cc: Christoph Hellwig <hch@xxxxxx> > Cc: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx> Bump, could this be applied please ? > --- > fs/configfs/file.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/fs/configfs/file.c b/fs/configfs/file.c > index 33b7ee3..bbc1252 100644 > --- a/fs/configfs/file.c > +++ b/fs/configfs/file.c > @@ -357,8 +357,6 @@ configfs_write_bin_file(struct file *file, const char __user *buf, > > len = simple_write_to_buffer(buffer->bin_buffer, > buffer->bin_buffer_size, ppos, buf, count); > - if (len > 0) > - *ppos += len; > out: > mutex_unlock(&buffer->mutex); > return len; > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
