seq_file: add seq_cpumask(), seq_nodemask()
Short enough reads from /proc/irq/*/smp_affinity return -EINVAL for no good reason. This became noticed with NR_CPUS=4096 patches, when length of printed representation of cpumask becase 1152, but cat(1) continued to read with 1024-byte chunks. bitmap_scnprintf() in good faith fills buffer, returns 1023, check returns -EINVAL. Fix it by switching to seq_file, so handler will just fill buffer and doesn't care about offsets, length, filling EOF and all this crap. For that add seq_bitmap(), and wrappers around it -- seq_cpumask() and seq_nodemask(). Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Paul Jackson <pj@sgi.com> Cc: Mike Travis <travis@sgi.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -443,6 +443,20 @@ int seq_dentry(struct seq_file *m, struct dentry *dentry, char *esc)
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return -1;
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}
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int seq_bitmap(struct seq_file *m, unsigned long *bits, unsigned int nr_bits)
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{
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size_t len = bitmap_scnprintf_len(nr_bits);
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if (m->count + len < m->size) {
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bitmap_scnprintf(m->buf + m->count, m->size - m->count,
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bits, nr_bits);
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m->count += len;
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return 0;
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}
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m->count = m->size;
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return -1;
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}
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static void *single_start(struct seq_file *p, loff_t *pos)
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{
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return NULL + (*pos == 0);
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@ -110,6 +110,7 @@ extern int __bitmap_weight(const unsigned long *bitmap, int bits);
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extern int bitmap_scnprintf(char *buf, unsigned int len,
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const unsigned long *src, int nbits);
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extern int bitmap_scnprintf_len(unsigned int nr_bits);
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extern int __bitmap_parse(const char *buf, unsigned int buflen, int is_user,
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unsigned long *dst, int nbits);
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extern int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,
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@ -4,6 +4,8 @@
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/mutex.h>
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#include <linux/cpumask.h>
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#include <linux/nodemask.h>
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struct seq_operations;
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struct file;
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@ -47,6 +49,16 @@ int seq_path(struct seq_file *, struct path *, char *);
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int seq_dentry(struct seq_file *, struct dentry *, char *);
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int seq_path_root(struct seq_file *m, struct path *path, struct path *root,
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char *esc);
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int seq_bitmap(struct seq_file *m, unsigned long *bits, unsigned int nr_bits);
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static inline int seq_cpumask(struct seq_file *m, cpumask_t *mask)
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{
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return seq_bitmap(m, mask->bits, NR_CPUS);
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}
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static inline int seq_nodemask(struct seq_file *m, nodemask_t *mask)
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{
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return seq_bitmap(m, mask->bits, MAX_NUMNODES);
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}
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int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
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int single_release(struct inode *, struct file *);
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11
lib/bitmap.c
11
lib/bitmap.c
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@ -315,6 +315,17 @@ int bitmap_scnprintf(char *buf, unsigned int buflen,
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}
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EXPORT_SYMBOL(bitmap_scnprintf);
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/**
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* bitmap_scnprintf_len - return buffer length needed to convert
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* bitmap to an ASCII hex string
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* @nr_bits: number of bits to be converted
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*/
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int bitmap_scnprintf_len(unsigned int nr_bits)
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{
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unsigned int nr_nibbles = ALIGN(nr_bits, 4) / 4;
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return nr_nibbles + ALIGN(nr_nibbles, CHUNKSZ / 4) / (CHUNKSZ / 4) - 1;
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}
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/**
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* __bitmap_parse - convert an ASCII hex string into a bitmap.
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* @buf: pointer to buffer containing string.
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