From dd05add7b2b6004c5fa3a1f276f56d8668f86b65 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sat, 26 Sep 2026 19:20:30 -0300 Subject: netfs: zero the tail of a short DIO/unbuffered read The buffered read collector zero-fills the tail of a short read that stops below the inode's i_size (netfs_clear_unread()), so a read that races an extending write still returns the expected number of bytes. The non-buffered collector path does no such thing: it just records how much was transferred. Add the same zero-fill for the non-buffered case, gated on NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short result from it is known to be safe to treat as a hole, as opposed to NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of the file and should be reported short as-is. Only CLEAR_TAIL should zero-fill here; a real EOF must stay a real short read. No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest, so this is inert on its own -- a following change teaches cifs to set it in the one case that needs it. Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item") Reviewed-by: David Howells Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- include/asm-generic/iomap.h | 95 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 include/asm-generic/iomap.h (limited to 'include/asm-generic/iomap.h') diff --git a/include/asm-generic/iomap.h b/include/asm-generic/iomap.h new file mode 100644 index 000000000..9f3f25d7f --- /dev/null +++ b/include/asm-generic/iomap.h @@ -0,0 +1,95 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __GENERIC_IO_H +#define __GENERIC_IO_H + +#include +#include + +/* + * These are the "generic" interfaces for doing new-style + * memory-mapped or PIO accesses. Architectures may do + * their own arch-optimized versions, these just act as + * wrappers around the old-style IO register access functions: + * read[bwl]/write[bwl]/in[bwl]/out[bwl] + * + * Don't include this directly, include it from . + */ + +/* + * Read/write from/to an (offsettable) iomem cookie. It might be a PIO + * access or a MMIO access, these functions don't care. The info is + * encoded in the hardware mapping set up by the mapping functions + * (or the cookie itself, depending on implementation and hw). + * + * The generic routines just encode the PIO/MMIO as part of the + * cookie, and coldly assume that the MMIO IO mappings are not + * in the low address range. Architectures for which this is not + * true can't use this generic implementation. + */ +extern unsigned int ioread8(const void __iomem *); +extern unsigned int ioread16(const void __iomem *); +extern unsigned int ioread16be(const void __iomem *); +extern unsigned int ioread32(const void __iomem *); +extern unsigned int ioread32be(const void __iomem *); + +extern u64 __ioread64_lo_hi(const void __iomem *addr); +extern u64 __ioread64_hi_lo(const void __iomem *addr); +extern u64 __ioread64be_lo_hi(const void __iomem *addr); +extern u64 __ioread64be_hi_lo(const void __iomem *addr); + +extern void iowrite8(u8, void __iomem *); +extern void iowrite16(u16, void __iomem *); +extern void iowrite16be(u16, void __iomem *); +extern void iowrite32(u32, void __iomem *); +extern void iowrite32be(u32, void __iomem *); + +extern void __iowrite64_lo_hi(u64 val, void __iomem *addr); +extern void __iowrite64_hi_lo(u64 val, void __iomem *addr); +extern void __iowrite64be_lo_hi(u64 val, void __iomem *addr); +extern void __iowrite64be_hi_lo(u64 val, void __iomem *addr); + +/* + * "string" versions of the above. Note that they + * use native byte ordering for the accesses (on + * the assumption that IO and memory agree on a + * byte order, and CPU byteorder is irrelevant). + * + * They do _not_ update the port address. If you + * want MMIO that copies stuff laid out in MMIO + * memory across multiple ports, use "memcpy_toio()" + * and friends. + */ +extern void ioread8_rep(const void __iomem *port, void *buf, unsigned long count); +extern void ioread16_rep(const void __iomem *port, void *buf, unsigned long count); +extern void ioread32_rep(const void __iomem *port, void *buf, unsigned long count); + +extern void iowrite8_rep(void __iomem *port, const void *buf, unsigned long count); +extern void iowrite16_rep(void __iomem *port, const void *buf, unsigned long count); +extern void iowrite32_rep(void __iomem *port, const void *buf, unsigned long count); + +#ifdef CONFIG_HAS_IOPORT_MAP +/* Create a virtual mapping cookie for an IO port range */ +extern void __iomem *ioport_map(unsigned long port, unsigned int nr); +extern void ioport_unmap(void __iomem *); +#endif + +#ifndef ioremap_wc +#define ioremap_wc ioremap +#endif + +#ifndef ioremap_wt +#define ioremap_wt ioremap +#endif + +#ifndef ioremap_np +/* See the comment in asm-generic/io.h about ioremap_np(). */ +#define ioremap_np ioremap_np +static inline void __iomem *ioremap_np(phys_addr_t offset, size_t size) +{ + return NULL; +} +#endif + +#include + +#endif -- cgit v1.3.1