linux/fs/sysfs, branch v4.1

sysfs: Only accept read/write permissions for file attributes

2015-03-25T12:27:57Z

For sysfs file attributes, only read and write permissions make sense. Mask provided attribute permissions accordingly and send a warning to the console if invalid permission bits are set. This patch is originally from Guenter [1] and includes the fixup explained in the thread, that is printing permissions in octal format and limiting the scope of attributes to SYSFS_PREALLOC | 0664. [1] https://lkml.org/lkml/2015/1/19/599 Signed-off-by: Vivien Didelot Reviewed-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

sysfs: Use only return value from is_visible for the file mode

2015-03-25T12:27:57Z

Up to now, is_visible can only be used to either remove visibility of a file entirely or to add permissions, but not to reduce permissions. This makes it impossible, for example, to use DEVICE_ATTR_RW to define file attributes and reduce permissions to read-only. This behavior is undesirable and unnecessarily complicates code which needs to reduce permissions; instead of just returning the desired permissions, it has to ensure that the permissions in the attribute variable declaration only reflect the minimal permissions ever needed. Change semantics of is_visible to only use the permissions returned from it instead of oring the returned value with the hard-coded permissions. Signed-off-by: Guenter Roeck Signed-off-by: Vivien Didelot Signed-off-by: Greg Kroah-Hartman

Merge tag 'driver-core-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2015-02-15T19:11:47Z

Pull driver core patches from Greg KH: "Really tiny set of patches for this kernel. Nothing major, all described in the shortlog and have been in linux-next for a while" * tag 'driver-core-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: sysfs: fix warning when creating a sysfs group without attributes firmware_loader: handle timeout via wait_for_completion_interruptible_timeout() firmware_loader: abort request if wait_for_completion is interrupted firmware: Correct function name in comment device: Change dev_ logging functions to return void device: Fix dev_dbg_once macro

kernfs: remove KERNFS_STATIC_NAME

2015-02-14T05:21:36Z

When a new kernfs node is created, KERNFS_STATIC_NAME is used to avoid making a separate copy of its name. It's currently only used for sysfs attributes whose filenames are required to stay accessible and unchanged. There are rare exceptions where these names are allocated and formatted dynamically but for the vast majority of cases they're consts in the rodata section. Now that kernfs is converted to use kstrdup_const() and kfree_const(), there's little point in keeping KERNFS_STATIC_NAME around. Remove it. Signed-off-by: Tejun Heo Cc: Andrzej Hajda Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sysfs: fix warning when creating a sysfs group without attributes

2015-02-03T23:50:31Z

When attempting to create a gropu without attrs, the warning prints the name of the group. However, the check for name being a NULL pointer is wrong: it uses the pointer to the name when it's NULL. Fix it to use the name if present, otherwise just put an empty string. Cc: Bruno Prémont Cc: Greg Kroah-Hartman Signed-off-by: Javi Merino Signed-off-by: Greg Kroah-Hartman

sysfs/kernfs: make read requests on pre-alloc files use the buffer.

2014-11-07T18:54:38Z

To match the previous patch which used the pre-alloc buffer for writes, this patch causes reads to use the same buffer. This is not strictly necessary as the current seq_read() will allocate on first read, so user-space can trigger the required pre-alloc. But consistency is valuable. The read function is somewhat simpler than seq_read() and, for example, does not support reading from an offset into the file: reads must be at the start of the file. As seq_read() does not use the prealloc buffer, ->seq_show is incompatible with ->prealloc and caused an EINVAL return from open(). sysfs code which calls into kernfs always chooses the correct function. As the buffer is shared with writes and other reads, the mutex is extended to cover the copy_to_user. Signed-off-by: NeilBrown Reviewed-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

sysfs/kernfs: allow attributes to request write buffer be pre-allocated.

2014-11-07T18:53:25Z

md/raid allows metadata management to be performed in user-space. A various times, particularly on device failure, the metadata needs to be updated before further writes can be permitted. This means that the user-space program which updates metadata much not block on writeout, and so must not allocate memory. mlockall(MCL_CURRENT|MCL_FUTURE) and pre-allocation can avoid all memory allocation issues for user-memory, but that does not help kernel memory. Several kernel objects can be pre-allocated. e.g. files opened before any writes to the array are permitted. However some kernel allocation happens in places that cannot be pre-allocated. In particular, writes to sysfs files (to tell md that it can now allow writes to the array) allocate a buffer using GFP_KERNEL. This patch allows attributes to be marked as "PREALLOC". In that case the maximal buffer is allocated when the file is opened, and then used on each write instead of allocating a new buffer. As the same buffer is now shared for all writes on the same file description, the mutex is extended to cover full use of the buffer including the copy_from_user(). The new __ATTR_PREALLOC() 'or's a new flag in to the 'mode', which is inspected by sysfs_add_file_mode_ns() to determine if the file should be marked as requiring prealloc. Despite the comment, we *do* use ->seq_show together with ->prealloc in this patch. The next patch fixes that. Signed-off-by: NeilBrown Reviewed-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

fs: sysfs: return EGBIG on write if offset is larger than file size

2014-11-07T18:52:20Z

According to the user expectations common utilities like dd or sh redirection operator > should work correctly over binary files from sysfs. At the moment doing excessive write can not be completed: write(1, "\0\0\0\0\0\0\0\0", 8) = 4 write(1, "\0\0\0\0", 4) = 0 write(1, "\0\0\0\0", 4) = 0 write(1, "\0\0\0\0", 4) = 0 ... Fix the problem by returning EFBIG described in man 2 write. Signed-off-by: Vladimir Zapolskiy Cc: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

kernfs: move the last knowledge of sysfs out from kernfs

2014-05-27T21:33:17Z

There is still one residue of sysfs remaining: the sb_magic SYSFS_MAGIC. However this should be kernfs user specific, so this patch moves it out. Kerrnfs user should specify their magic number while mouting. Signed-off-by: Jianyu Zhan Acked-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

sysfs: fix attribute_group bin file path on removal

2014-05-27T21:33:17Z

Cody Schafer already fixed binary file creation for attribute groups, see [1]. This patch makes the appropriate changes for binary file removal of attribute groups. [1]: http://lkml.org/lkml/2014/2/27/832 Signed-off-by: Robert ABEL Signed-off-by: Greg Kroah-Hartman