diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0568-configfs-Remove-ppos-increment-in-configfs_write_bin.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0568-configfs-Remove-ppos-increment-in-configfs_write_bin.patch | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0568-configfs-Remove-ppos-increment-in-configfs_write_bin.patch b/target/linux/brcm2708/patches-4.4/0568-configfs-Remove-ppos-increment-in-configfs_write_bin.patch new file mode 100644 index 0000000..fcc2d60 --- /dev/null +++ b/target/linux/brcm2708/patches-4.4/0568-configfs-Remove-ppos-increment-in-configfs_write_bin.patch @@ -0,0 +1,54 @@ +From b928add95c9ddaa70b591da00d129558535d14d3 Mon Sep 17 00:00:00 2001 +From: Marek Vasut <marex@denx.de> +Date: Wed, 18 May 2016 16:16:51 +0200 +Subject: [PATCH] configfs: Remove ppos increment in configfs_write_bin_file + +[ Back-port of f8608985f851c917b3884b692d8e326b0210d34e ] + +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@denx.de> +Cc: Geert Uytterhoeven <geert+renesas@glider.be> +Cc: Christoph Hellwig <hch@lst.de> +Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com> +--- + fs/configfs/file.c | 2 -- + 1 file changed, 2 deletions(-) + +diff --git a/fs/configfs/file.c b/fs/configfs/file.c +index 3687187..6e322f2 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; +-- +2.1.4 + |