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 --- scripts/include/hashtable.h | 98 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 scripts/include/hashtable.h (limited to 'scripts/include/hashtable.h') diff --git a/scripts/include/hashtable.h b/scripts/include/hashtable.h new file mode 100644 index 000000000..45abcb12b --- /dev/null +++ b/scripts/include/hashtable.h @@ -0,0 +1,98 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef HASHTABLE_H +#define HASHTABLE_H + +#include "array_size.h" +#include "list.h" + +#define HASH_SIZE(name) (ARRAY_SIZE(name)) + +#define HASHTABLE_DECLARE(name, size) struct hlist_head name[size] + +#define HASHTABLE_DEFINE(name, size) \ + HASHTABLE_DECLARE(name, size) = \ + { [0 ... ((size) - 1)] = HLIST_HEAD_INIT } + +#define hash_head(table, key) (&(table)[(key) % HASH_SIZE(table)]) + +static inline void __hash_init(struct hlist_head *ht, unsigned int sz) +{ + unsigned int i; + + for (i = 0; i < sz; i++) + INIT_HLIST_HEAD(&ht[i]); +} + +/** + * hash_init - initialize a hash table + * @table: hashtable to be initialized + * + * This has to be a macro since HASH_SIZE() will not work on pointers since + * it calculates the size during preprocessing. + */ +#define hash_init(table) __hash_init(table, HASH_SIZE(table)) + +/** + * hash_add - add an object to a hashtable + * @table: hashtable to add to + * @node: the &struct hlist_node of the object to be added + * @key: the key of the object to be added + */ +#define hash_add(table, node, key) \ + hlist_add_head(node, hash_head(table, key)) + +/** + * hash_del - remove an object from a hashtable + * @node: &struct hlist_node of the object to remove + */ +static inline void hash_del(struct hlist_node *node) +{ + hlist_del_init(node); +} + +/** + * hash_for_each - iterate over a hashtable + * @table: hashtable to iterate + * @obj: the type * to use as a loop cursor for each entry + * @member: the name of the hlist_node within the struct + */ +#define hash_for_each(table, obj, member) \ + for (int _bkt = 0; _bkt < HASH_SIZE(table); _bkt++) \ + hlist_for_each_entry(obj, &table[_bkt], member) + +/** + * hash_for_each_safe - iterate over a hashtable safe against removal of + * hash entry + * @table: hashtable to iterate + * @obj: the type * to use as a loop cursor for each entry + * @tmp: a &struct hlist_node used for temporary storage + * @member: the name of the hlist_node within the struct + */ +#define hash_for_each_safe(table, obj, tmp, member) \ + for (int _bkt = 0; _bkt < HASH_SIZE(table); _bkt++) \ + hlist_for_each_entry_safe(obj, tmp, &table[_bkt], member) + +/** + * hash_for_each_possible - iterate over all possible objects hashing to the + * same bucket + * @table: hashtable to iterate + * @obj: the type * to use as a loop cursor for each entry + * @member: the name of the hlist_node within the struct + * @key: the key of the objects to iterate over + */ +#define hash_for_each_possible(table, obj, member, key) \ + hlist_for_each_entry(obj, hash_head(table, key), member) + +/** + * hash_for_each_possible_safe - iterate over all possible objects hashing to the + * same bucket safe against removals + * @table: hashtable to iterate + * @obj: the type * to use as a loop cursor for each entry + * @tmp: a &struct hlist_node used for temporary storage + * @member: the name of the hlist_node within the struct + * @key: the key of the objects to iterate over + */ +#define hash_for_each_possible_safe(table, obj, tmp, member, key) \ + hlist_for_each_entry_safe(obj, tmp, hash_head(table, key), member) + +#endif /* HASHTABLE_H */ -- cgit v1.3.1