| Message ID | 20201204170319.20383-1-laniel_francis@privacyrequired.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Replace strstarts() by str_has_prefix() | expand |
On Fri, 2020-12-04 at 18:03 +0100, laniel_francis@privacyrequired.com wrote: > In this patch set, I replaced all calls to strstarts() by calls to > str_has_prefix(). Indeed, the kernel has two functions to test if a > string begins with an other: > 1. strstarts() which returns a bool, so 1 if the string begins with > the prefix,0 otherwise. > 2. str_has_prefix() which returns the length of the prefix or 0. > > str_has_prefix() was introduced later than strstarts(), in commit > 495d714ad140 which also stated that str_has_prefix() should replace > strstarts(). This is what this patch set does. What's the reason why? If you look at the use cases for the replacement of strstart() they're all cases where we need to know the length we're skipping and this is hard coded, leading to potential errors later. This is a classic example: 3d739c1f6156 ("tracing: Use the return of str_has_prefix() to remove open coded numbers"). However you're not doing this transformation in the conversion, so the conversion is pretty useless. I also see no case for replacing strstart() where we're using it simply as a boolean without needing to know the length of the prefix. James
From: Francis Laniel <laniel_francis@privacyrequired.com> Hi. First, I hope you are fine and the same for your relatives. In this patch set, I replaced all calls to strstarts() by calls to str_has_prefix(). Indeed, the kernel has two functions to test if a string begins with an other: 1. strstarts() which returns a bool, so 1 if the string begins with the prefix, 0 otherwise. 2. str_has_prefix() which returns the length of the prefix or 0. str_has_prefix() was introduced later than strstarts(), in commit 495d714ad140 which also stated that str_has_prefix() should replace strstarts(). This is what this patch set does. Concerning the patches, the modifications cover different areas of the kernel. I compiled all of them and they compile smoothly. Unfortunately, I did not test all of them, so here are the status of the patches regarding test: 1. Tested with qemu-system-arm using insmod. 2. I do not have access to a bcm47xx MIPS CPU an qemu-system-mips does not emulate this board. 3. Tested with qemu-system-x86_64 calling crypto_alloc_skcipher("essiv(authenc(hmac(sha256),cbc(aes)),sha256)", 0, 0) through LKDTM. 4. Tested with qemu-system-x86_64 using crypsetup. 5. I do not have access to a renesas board and I lack some context to test it with qemu-system-arm. 6. I do not have access to an OMAP board and I lack some context to test it with qemu-system-arm. 7. I did not find how to boot from the EFI_STUB with qemu. If you know how to do, I would be happy to try running this code. 8. I ran qemu-system-x86_64 with a floppy disk attached but impossible to go through this module code... 9. I do not have access to a bcm63xx MIPS CPU an qemu-system-mips does not emulate this board. 10. Tested with qemu-system-x86_64 using insmod. 11. I do not have access to an AM335x or DA8xx platforms and I lack some context to test it with qemu-system-arm. If you see a way to improve the patches or if I did something wrong with the mail do not hesitate to ask. Best regards. Francis Laniel (12): arm: Replace strstarts() by str_has_prefix(). mips: Replace strstarts() by str_has_prefix(). crypto: Replace strstarts() by str_has_prefix(). device-mapper: Replace strstarts() by str_has_prefix(). renesas: Replace strstarts() by str_has_prefix(). omap: Replace strstarts() by str_has_prefix(). efi: Replace strstarts() by str_has_prefix(). ide: Replace strstarts() by str_has_prefix(). mips: Replace strstarts() by str_has_prefix(). module: Replace strstarts() by str_has_prefix(). musb: Replace strstarts() by str_has_prefix(). string.h: Remove strstarts(). arch/arm/kernel/module.c | 12 +++++------ arch/mips/bcm47xx/board.c | 4 ++-- arch/mips/bcm63xx/boards/board_bcm963xx.c | 2 +- crypto/essiv.c | 2 +- .../firmware/efi/libstub/efi-stub-helper.c | 2 +- drivers/firmware/efi/libstub/gop.c | 10 +++++----- drivers/gpu/drm/omapdrm/dss/base.c | 2 +- drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 2 +- drivers/ide/ide-floppy.c | 4 ++-- drivers/md/dm-crypt.c | 4 ++-- drivers/usb/musb/musb_cppi41.c | 4 ++-- drivers/usb/musb/musb_debugfs.c | 20 +++++++++---------- include/linux/string.h | 10 ---------- kernel/module.c | 6 +++--- 14 files changed, 37 insertions(+), 47 deletions(-)