linux/block/partitions/cmdline.c, branch master

block: partitions: Replace pp_buf with struct seq_buf

2026-03-21T14:27:08Z

In preparation for removing the strlcat API[1], replace the char *pp_buf with a struct seq_buf, which tracks the current write position and remaining space internally. This allows for: - Direct use of seq_buf_printf() in place of snprintf()+strlcat() pairs, eliminating local tmp buffers throughout. - Adjacent strlcat() calls that build strings piece-by-piece (e.g., strlcat("["); strlcat(name); strlcat("]")) to be collapsed into single seq_buf_printf() calls. - Simpler call sites: seq_buf_puts() takes only the buffer and string, with no need to pass PAGE_SIZE at every call. The backing buffer allocation is unchanged (__get_free_page), and the output path uses seq_buf_str() to NUL-terminate before passing to printk(). Link: https://github.com/KSPP/linux/issues/370 [1] Cc: Andy Shevchenko Cc: Josh Law Signed-off-by: Kees Cook Reviewed-by: Josh Law Link: https://patch.msgid.link/20260321004840.work.670-kees@kernel.org Signed-off-by: Jens Axboe

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51Z

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28Z

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

block: add support for defining read-only partitions

2024-10-22T14:14:56Z

Add support for defining read-only partitions and complete support for it in the cmdline partition parser as the additional "ro" after a partition is scanned but never actually applied. Signed-off-by: Christian Marangi Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20241002221306.4403-2-ansuelsmth@gmail.com Signed-off-by: Jens Axboe

block: fix and simplify blkdevparts= cmdline parsing

2024-05-03T15:57:53Z

Fix the cmdline parsing of the "blkdevparts=" parameter using strsep(), which makes the code simpler. Before commit 146afeb235cc ("block: use strscpy() to instead of strncpy()"), we used a strncpy() to copy a block device name and partition names. The commit simply replaced a strncpy() and NULL termination with a strscpy(). It did not update calculations of length passed to strscpy(). While the length passed to strncpy() is just a length of valid characters without NULL termination ('\0'), strscpy() takes it as a length of the destination buffer, including a NULL termination. Since the source buffer is not necessarily NULL terminated, the current code copies "length - 1" characters and puts a NULL character in the destination buffer. It replaces the last character with NULL and breaks the parsing. As an example, that buffer will be passed to parse_parts() and breaks parsing sub-partitions due to the missing ')' at the end, like the following. example (Check Point V-80 & OpenWrt): - Linux Kernel 6.6 [ 0.000000] Kernel command line: console=ttyS0,115200 earlycon=uart8250,mmio32,0xf0512000 crashkernel=30M mvpp2x.queue_mode=1 blkdevparts=mmcblk1:48M@10M(kernel-1),1M(dtb-1),720M(rootfs-1),48M(kernel-2),1M(dtb-2),720M(rootfs-2),300M(default_sw),650M(logs),1M(preset_cfg),1M(adsl),-(storage) maxcpus=4 ... [ 0.884016] mmc1: new HS200 MMC card at address 0001 [ 0.889951] mmcblk1: mmc1:0001 004GA0 3.69 GiB [ 0.895043] cmdline partition format is invalid. [ 0.895704] mmcblk1: p1 [ 0.903447] mmcblk1boot0: mmc1:0001 004GA0 2.00 MiB [ 0.908667] mmcblk1boot1: mmc1:0001 004GA0 2.00 MiB [ 0.913765] mmcblk1rpmb: mmc1:0001 004GA0 512 KiB, chardev (248:0) 1. "48M@10M(kernel-1),..." is passed to strscpy() with length=17 from parse_parts() 2. strscpy() returns -E2BIG and the destination buffer has "48M@10M(kernel-1\0" 3. "48M@10M(kernel-1\0" is passed to parse_subpart() 4. parse_subpart() fails to find ')' when parsing a partition name, and returns error - Linux Kernel 6.1 [ 0.000000] Kernel command line: console=ttyS0,115200 earlycon=uart8250,mmio32,0xf0512000 crashkernel=30M mvpp2x.queue_mode=1 blkdevparts=mmcblk1:48M@10M(kernel-1),1M(dtb-1),720M(rootfs-1),48M(kernel-2),1M(dtb-2),720M(rootfs-2),300M(default_sw),650M(logs),1M(preset_cfg),1M(adsl),-(storage) maxcpus=4 ... [ 0.953142] mmc1: new HS200 MMC card at address 0001 [ 0.959114] mmcblk1: mmc1:0001 004GA0 3.69 GiB [ 0.964259] mmcblk1: p1(kernel-1) p2(dtb-1) p3(rootfs-1) p4(kernel-2) p5(dtb-2) 6(rootfs-2) p7(default_sw) p8(logs) p9(preset_cfg) p10(adsl) p11(storage) [ 0.979174] mmcblk1boot0: mmc1:0001 004GA0 2.00 MiB [ 0.984674] mmcblk1boot1: mmc1:0001 004GA0 2.00 MiB [ 0.989926] mmcblk1rpmb: mmc1:0001 004GA0 512 KiB, chardev (248:0 By the way, strscpy() takes a length of destination buffer and it is often confusing when copying characters with a specified length. Using strsep() helps to separate the string by the specified character. Then, we can use strscpy() naturally with the size of the destination buffer. Separating the string on the fly is also useful to omit the redundant string copy, reducing memory usage and improve the code readability. Fixes: 146afeb235cc ("block: use strscpy() to instead of strncpy()") Suggested-by: Naohiro Aota Signed-off-by: INAGAKI Hiroshi Reviewed-by: Daniel Golle Link: https://lore.kernel.org/r/20240421074005.565-1-musashino.open@gmail.com Signed-off-by: Jens Axboe

block: use strscpy() to instead of strncpy()

2023-08-23T00:07:50Z

The implementation of strscpy() is more robust and safer. That's now the recommended way to copy NUL terminated strings. Signed-off-by: Xu Panda Signed-off-by: Yang Yang Reviewed-by: Justin Stitt Link: https://lore.kernel.org/r/202212031422587503771@zte.com.cn Signed-off-by: Jens Axboe

block: store a gendisk in struct parsed_partitions

2021-08-12T16:31:35Z

Partition scanning only happens on the whole device, so pass a struct gendisk instead of the whole device block_device to the scanners. This allows to simplify printing the device name in various places as the disk name is available in disk->name. Signed-off-by: Christoph Hellwig Reviewed-by: Stefan Haberland Link: https://lore.kernel.org/r/20210810154512.1809898-2-hch@lst.de Signed-off-by: Jens Axboe

block: remove cmdline-parser.c

2021-08-02T19:37:28Z

cmdline-parser.c is only used by the cmdline faux partition format, so merge the code into that and avoid an indirect call. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20210728053756.409654-1-hch@lst.de Signed-off-by: Jens Axboe

block: declare all partition detection routines in check.h

2020-03-24T13:57:08Z

There is no good reason to include one header per partition type in core.c. Instead move the prototypes for the detection routins to check.h, and remove all now empty headers in block/partitions/. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

docs: block: convert to ReST

2019-07-15T12:20:27Z

Rename the block documentation files to ReST, add an index for them and adjust in order to produce a nice html output via the Sphinx build system. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab