5.15-stable review patch. If anyone has any objections, please let me know.
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From: Linus Torvalds torvalds@linux-foundation.org
[ Upstream commit 4477b39c32fdc03363affef4b11d48391e6dc9ff ]
Commit 3a7e02c040b1 ("minmax: avoid overly complicated constant expressions in VM code") added the simpler MIN_T/MAX_T macros in order to avoid some excessive expansion from the rather complicated regular min/max macros.
The complexity of those macros stems from two issues:
(a) trying to use them in situations that require a C constant expression (in static initializers and for array sizes)
(b) the type sanity checking
and MIN_T/MAX_T avoids both of these issues.
Now, in the whole (long) discussion about all this, it was pointed out that the whole type sanity checking is entirely unnecessary for min_t/max_t which get a fixed type that the comparison is done in.
But that still leaves min_t/max_t unnecessarily complicated due to worries about the C constant expression case.
However, it turns out that there really aren't very many cases that use min_t/max_t for this, and we can just force-convert those.
This does exactly that.
Which in turn will then allow for much simpler implementations of min_t()/max_t(). All the usual "macros in all upper case will evaluate the arguments multiple times" rules apply.
We should do all the same things for the regular min/max() vs MIN/MAX() cases, but that has the added complexity of various drivers defining their own local versions of MIN/MAX, so that needs another level of fixes first.
Link: https://lore.kernel.org/all/b47fad1d0cf8449886ad148f8c013dae@AcuMS.aculab.co... Cc: David Laight David.Laight@aculab.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- V2 -> V3: Fix fs/erofs/zdata.h to use MIN_T instead of min_t to fix build on the following patch: In file included from ./include/linux/kernel.h:16, from ./include/linux/list.h:9, from ./include/linux/wait.h:7, from ./include/linux/wait_bit.h:8, from ./include/linux/fs.h:6, from fs/erofs/internal.h:10, from fs/erofs/zdata.h:9, from fs/erofs/zdata.c:6: fs/erofs/zdata.c: In function ‘z_erofs_decompress_pcluster’: fs/erofs/zdata.h:185:61: error: ISO C90 forbids variable length array ‘pages_onstack’ [-Werror=vla] 185 | min_t(unsigned int, THREAD_SIZE / 8 / sizeof(struct page *), 96U) | ^~~~ ./include/linux/minmax.h:49:23: note: in definition of macro ‘__cmp_once_unique’ 49 | ({ type ux = (x); type uy = (y); __cmp(op, ux, uy); }) | ^ ./include/linux/minmax.h:164:27: note: in expansion of macro ‘__cmp_once’ 164 | #define min_t(type, x, y) __cmp_once(min, type, x, y) | ^~~~~~~~~~ fs/erofs/zdata.h:185:9: note: in expansion of macro ‘min_t’ 185 | min_t(unsigned int, THREAD_SIZE / 8 / sizeof(struct page *), 96U) | ^~~~~ fs/erofs/zdata.c:847:36: note: in expansion of macro ‘Z_EROFS_VMAP_ONSTACK_PAGES’ 847 | struct page *pages_onstack[Z_EROFS_VMAP_ONSTACK_PAGES]; | ^~~~~~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors
V1 -> V2: Use `[ Upstream commit <HASH> ]` instead of `commit <HASH> upstream.` like in all other patches.
arch/x86/mm/pgtable.c | 2 +- drivers/edac/sb_edac.c | 4 ++-- drivers/gpu/drm/drm_color_mgmt.c | 2 +- drivers/md/dm-integrity.c | 2 +- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +- fs/erofs/zdata.h | 2 +- net/ipv4/proc.c | 2 +- net/ipv6/proc.c | 2 +- 8 files changed, 9 insertions(+), 9 deletions(-)
--- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -107,7 +107,7 @@ static inline void pgd_list_del(pgd_t *p #define UNSHARED_PTRS_PER_PGD \ (SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD) #define MAX_UNSHARED_PTRS_PER_PGD \ - max_t(size_t, KERNEL_PGD_BOUNDARY, PTRS_PER_PGD) + MAX_T(size_t, KERNEL_PGD_BOUNDARY, PTRS_PER_PGD)
static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm) --- a/drivers/edac/sb_edac.c +++ b/drivers/edac/sb_edac.c @@ -109,8 +109,8 @@ static const u32 knl_interleave_list[] = 0x104, 0x10c, 0x114, 0x11c, /* 20-23 */ }; #define MAX_INTERLEAVE \ - (max_t(unsigned int, ARRAY_SIZE(sbridge_interleave_list), \ - max_t(unsigned int, ARRAY_SIZE(ibridge_interleave_list), \ + (MAX_T(unsigned int, ARRAY_SIZE(sbridge_interleave_list), \ + MAX_T(unsigned int, ARRAY_SIZE(ibridge_interleave_list), \ ARRAY_SIZE(knl_interleave_list))))
struct interleave_pkg { --- a/drivers/gpu/drm/drm_color_mgmt.c +++ b/drivers/gpu/drm/drm_color_mgmt.c @@ -528,7 +528,7 @@ int drm_plane_create_color_properties(st { struct drm_device *dev = plane->dev; struct drm_property *prop; - struct drm_prop_enum_list enum_list[max_t(int, DRM_COLOR_ENCODING_MAX, + struct drm_prop_enum_list enum_list[MAX_T(int, DRM_COLOR_ENCODING_MAX, DRM_COLOR_RANGE_MAX)]; int i, len;
--- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -2536,7 +2536,7 @@ static void do_journal_write(struct dm_i unlikely(from_replay) && #endif ic->internal_hash) { - char test_tag[max_t(size_t, HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)]; + char test_tag[MAX_T(size_t, HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
integrity_sector_checksum(ic, sec + ((l - j) << ic->sb->log2_sectors_per_block), (char *)access_journal_data(ic, i, l), test_tag); --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -2805,7 +2805,7 @@ static void stmmac_dma_interrupt(struct u32 channels_to_check = tx_channel_count > rx_channel_count ? tx_channel_count : rx_channel_count; u32 chan; - int status[max_t(u32, MTL_MAX_TX_QUEUES, MTL_MAX_RX_QUEUES)]; + int status[MAX_T(u32, MTL_MAX_TX_QUEUES, MTL_MAX_RX_QUEUES)];
/* Make sure we never check beyond our status buffer. */ if (WARN_ON_ONCE(channels_to_check > ARRAY_SIZE(status))) --- a/fs/erofs/zdata.h +++ b/fs/erofs/zdata.h @@ -182,7 +182,7 @@ static inline void z_erofs_onlinepage_en }
#define Z_EROFS_VMAP_ONSTACK_PAGES \ - min_t(unsigned int, THREAD_SIZE / 8 / sizeof(struct page *), 96U) + MIN_T(unsigned int, THREAD_SIZE / 8 / sizeof(struct page *), 96U) #define Z_EROFS_VMAP_GLOBAL_PAGES 2048
#endif --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -43,7 +43,7 @@ #include <net/sock.h> #include <net/raw.h>
-#define TCPUDP_MIB_MAX max_t(u32, UDP_MIB_MAX, TCP_MIB_MAX) +#define TCPUDP_MIB_MAX MAX_T(u32, UDP_MIB_MAX, TCP_MIB_MAX)
/* * Report socket allocation statistics [mea@utu.fi] --- a/net/ipv6/proc.c +++ b/net/ipv6/proc.c @@ -27,7 +27,7 @@ #include <net/ipv6.h>
#define MAX4(a, b, c, d) \ - max_t(u32, max_t(u32, a, b), max_t(u32, c, d)) + MAX_T(u32, MAX_T(u32, a, b), MAX_T(u32, c, d)) #define SNMP_MIB_MAX MAX4(UDP_MIB_MAX, TCP_MIB_MAX, \ IPSTATS_MIB_MAX, ICMP_MIB_MAX)