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authorStefani Seibold <stefani@seibold.net>2009-12-21 14:37:32 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-22 14:17:56 -0800
commit86d4880313603810901f639ccb5c88ff13d4ad3c (patch)
treec182d890b5c96a1143b70b00b93e3fc4a9263555 /include/linux
parenta121f24accac1600bf5b6fb1e12eeabdfed7cb1a (diff)
kfifo: add record handling functions
Add kfifo_in_rec() - puts some record data into the FIFO Add kfifo_out_rec() - gets some record data from the FIFO Add kfifo_from_user_rec() - puts some data from user space into the FIFO Add kfifo_to_user_rec() - gets data from the FIFO and write it to user space Add kfifo_peek_rec() - gets the size of the next FIFO record field Add kfifo_skip_rec() - skip the next fifo out record Add kfifo_avail_rec() - determinate the number of bytes available in a record FIFO Signed-off-by: Stefani Seibold <stefani@seibold.net> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com> Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/kfifo.h330
1 files changed, 330 insertions, 0 deletions
diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h
index d3230fb08bc..486e8ad3bb5 100644
--- a/include/linux/kfifo.h
+++ b/include/linux/kfifo.h
@@ -278,4 +278,334 @@ static inline unsigned int __kfifo_off(struct kfifo *fifo, unsigned int off)
return off & (fifo->size - 1);
}
+/**
+ * __kfifo_peek_n internal helper function for determinate the length of
+ * the next record in the fifo
+ */
+static inline unsigned int __kfifo_peek_n(struct kfifo *fifo,
+ unsigned int recsize)
+{
+#define __KFIFO_GET(fifo, off, shift) \
+ ((fifo)->buffer[__kfifo_off((fifo), (fifo)->out+(off))] << (shift))
+
+ unsigned int l;
+
+ l = __KFIFO_GET(fifo, 0, 0);
+
+ if (--recsize)
+ l |= __KFIFO_GET(fifo, 1, 8);
+
+ return l;
+#undef __KFIFO_GET
+}
+
+/**
+ * __kfifo_poke_n internal helper function for storing the length of
+ * the next record into the fifo
+ */
+static inline void __kfifo_poke_n(struct kfifo *fifo,
+ unsigned int recsize, unsigned int n)
+{
+#define __KFIFO_PUT(fifo, off, val, shift) \
+ ( \
+ (fifo)->buffer[__kfifo_off((fifo), (fifo)->in+(off))] = \
+ (unsigned char)((val) >> (shift)) \
+ )
+
+ __KFIFO_PUT(fifo, 0, n, 0);
+
+ if (--recsize)
+ __KFIFO_PUT(fifo, 1, n, 8);
+#undef __KFIFO_PUT
+}
+
+/**
+ * __kfifo_in_... internal functions for put date into the fifo
+ * do not call it directly, use kfifo_in_rec() instead
+ */
+extern unsigned int __kfifo_in_n(struct kfifo *fifo,
+ const void *from, unsigned int n, unsigned int recsize);
+
+extern unsigned int __kfifo_in_generic(struct kfifo *fifo,
+ const void *from, unsigned int n, unsigned int recsize);
+
+static inline unsigned int __kfifo_in_rec(struct kfifo *fifo,
+ const void *from, unsigned int n, unsigned int recsize)
+{
+ unsigned int ret;
+
+ ret = __kfifo_in_n(fifo, from, n, recsize);
+
+ if (likely(ret == 0)) {
+ if (recsize)
+ __kfifo_poke_n(fifo, recsize, n);
+ __kfifo_add_in(fifo, n + recsize);
+ }
+ return ret;
+}
+
+/**
+ * kfifo_in_rec - puts some record data into the FIFO
+ * @fifo: the fifo to be used.
+ * @from: the data to be added.
+ * @n: the length of the data to be added.
+ * @recsize: size of record field
+ *
+ * This function copies @n bytes from the @from into the FIFO and returns
+ * the number of bytes which cannot be copied.
+ * A returned value greater than the @n value means that the record doesn't
+ * fit into the buffer.
+ *
+ * Note that with only one concurrent reader and one concurrent
+ * writer, you don't need extra locking to use these functions.
+ */
+static inline __must_check unsigned int kfifo_in_rec(struct kfifo *fifo,
+ void *from, unsigned int n, unsigned int recsize)
+{
+ if (!__builtin_constant_p(recsize))
+ return __kfifo_in_generic(fifo, from, n, recsize);
+ return __kfifo_in_rec(fifo, from, n, recsize);
+}
+
+/**
+ * __kfifo_out_... internal functions for get date from the fifo
+ * do not call it directly, use kfifo_out_rec() instead
+ */
+extern unsigned int __kfifo_out_n(struct kfifo *fifo,
+ void *to, unsigned int reclen, unsigned int recsize);
+
+extern unsigned int __kfifo_out_generic(struct kfifo *fifo,
+ void *to, unsigned int n,
+ unsigned int recsize, unsigned int *total);
+
+static inline unsigned int __kfifo_out_rec(struct kfifo *fifo,
+ void *to, unsigned int n, unsigned int recsize,
+ unsigned int *total)
+{
+ unsigned int l;
+
+ if (!recsize) {
+ l = n;
+ if (total)
+ *total = l;
+ } else {
+ l = __kfifo_peek_n(fifo, recsize);
+ if (total)
+ *total = l;
+ if (n < l)
+ return l;
+ }
+
+ return __kfifo_out_n(fifo, to, l, recsize);
+}
+
+/**
+ * kfifo_out_rec - gets some record data from the FIFO
+ * @fifo: the fifo to be used.
+ * @to: where the data must be copied.
+ * @n: the size of the destination buffer.
+ * @recsize: size of record field
+ * @total: pointer where the total number of to copied bytes should stored
+ *
+ * This function copies at most @n bytes from the FIFO to @to and returns the
+ * number of bytes which cannot be copied.
+ * A returned value greater than the @n value means that the record doesn't
+ * fit into the @to buffer.
+ *
+ * Note that with only one concurrent reader and one concurrent
+ * writer, you don't need extra locking to use these functions.
+ */
+static inline __must_check unsigned int kfifo_out_rec(struct kfifo *fifo,
+ void *to, unsigned int n, unsigned int recsize,
+ unsigned int *total)
+
+{
+ if (!__builtin_constant_p(recsize))
+ return __kfifo_out_generic(fifo, to, n, recsize, total);
+ return __kfifo_out_rec(fifo, to, n, recsize, total);
+}
+
+/**
+ * __kfifo_from_user_... internal functions for transfer from user space into
+ * the fifo. do not call it directly, use kfifo_from_user_rec() instead
+ */
+extern unsigned int __kfifo_from_user_n(struct kfifo *fifo,
+ const void __user *from, unsigned int n, unsigned int recsize);
+
+extern unsigned int __kfifo_from_user_generic(struct kfifo *fifo,
+ const void __user *from, unsigned int n, unsigned int recsize);
+
+static inline unsigned int __kfifo_from_user_rec(struct kfifo *fifo,
+ const void __user *from, unsigned int n, unsigned int recsize)
+{
+ unsigned int ret;
+
+ ret = __kfifo_from_user_n(fifo, from, n, recsize);
+
+ if (likely(ret == 0)) {
+ if (recsize)
+ __kfifo_poke_n(fifo, recsize, n);
+ __kfifo_add_in(fifo, n + recsize);
+ }
+ return ret;
+}
+
+/**
+ * kfifo_from_user_rec - puts some data from user space into the FIFO
+ * @fifo: the fifo to be used.
+ * @from: pointer to the data to be added.
+ * @n: the length of the data to be added.
+ * @recsize: size of record field
+ *
+ * This function copies @n bytes from the @from into the
+ * FIFO and returns the number of bytes which cannot be copied.
+ *
+ * If the returned value is equal or less the @n value, the copy_from_user()
+ * functions has failed. Otherwise the record doesn't fit into the buffer.
+ *
+ * Note that with only one concurrent reader and one concurrent
+ * writer, you don't need extra locking to use these functions.
+ */
+static inline __must_check unsigned int kfifo_from_user_rec(struct kfifo *fifo,
+ const void __user *from, unsigned int n, unsigned int recsize)
+{
+ if (!__builtin_constant_p(recsize))
+ return __kfifo_from_user_generic(fifo, from, n, recsize);
+ return __kfifo_from_user_rec(fifo, from, n, recsize);
+}
+
+/**
+ * __kfifo_to_user_... internal functions for transfer fifo data into user space
+ * do not call it directly, use kfifo_to_user_rec() instead
+ */
+extern unsigned int __kfifo_to_user_n(struct kfifo *fifo,
+ void __user *to, unsigned int n, unsigned int reclen,
+ unsigned int recsize);
+
+extern unsigned int __kfifo_to_user_generic(struct kfifo *fifo,
+ void __user *to, unsigned int n, unsigned int recsize,
+ unsigned int *total);
+
+static inline unsigned int __kfifo_to_user_rec(struct kfifo *fifo,
+ void __user *to, unsigned int n,
+ unsigned int recsize, unsigned int *total)
+{
+ unsigned int l;
+
+ if (!recsize) {
+ l = n;
+ if (total)
+ *total = l;
+ } else {
+ l = __kfifo_peek_n(fifo, recsize);
+ if (total)
+ *total = l;
+ if (n < l)
+ return l;
+ }
+
+ return __kfifo_to_user_n(fifo, to, n, l, recsize);
+}
+
+/**
+ * kfifo_to_user_rec - gets data from the FIFO and write it to user space
+ * @fifo: the fifo to be used.
+ * @to: where the data must be copied.
+ * @n: the size of the destination buffer.
+ * @recsize: size of record field
+ * @total: pointer where the total number of to copied bytes should stored
+ *
+ * This function copies at most @n bytes from the FIFO to the @to.
+ * In case of an error, the function returns the number of bytes which cannot
+ * be copied.
+ * If the returned value is equal or less the @n value, the copy_to_user()
+ * functions has failed. Otherwise the record doesn't fit into the @to buffer.
+ *
+ * Note that with only one concurrent reader and one concurrent
+ * writer, you don't need extra locking to use these functions.
+ */
+static inline __must_check unsigned int kfifo_to_user_rec(struct kfifo *fifo,
+ void __user *to, unsigned int n, unsigned int recsize,
+ unsigned int *total)
+{
+ if (!__builtin_constant_p(recsize))
+ return __kfifo_to_user_generic(fifo, to, n, recsize, total);
+ return __kfifo_to_user_rec(fifo, to, n, recsize, total);
+}
+
+/**
+ * __kfifo_peek_... internal functions for peek into the next fifo record
+ * do not call it directly, use kfifo_peek_rec() instead
+ */
+extern unsigned int __kfifo_peek_generic(struct kfifo *fifo,
+ unsigned int recsize);
+
+/**
+ * kfifo_peek_rec - gets the size of the next FIFO record data
+ * @fifo: the fifo to be used.
+ * @recsize: size of record field
+ *
+ * This function returns the size of the next FIFO record in number of bytes
+ */
+static inline __must_check unsigned int kfifo_peek_rec(struct kfifo *fifo,
+ unsigned int recsize)
+{
+ if (!__builtin_constant_p(recsize))
+ return __kfifo_peek_generic(fifo, recsize);
+ if (!recsize)
+ return kfifo_len(fifo);
+ return __kfifo_peek_n(fifo, recsize);
+}
+
+/**
+ * __kfifo_skip_... internal functions for skip the next fifo record
+ * do not call it directly, use kfifo_skip_rec() instead
+ */
+extern void __kfifo_skip_generic(struct kfifo *fifo, unsigned int recsize);
+
+static inline void __kfifo_skip_rec(struct kfifo *fifo,
+ unsigned int recsize)
+{
+ unsigned int l;
+
+ if (recsize) {
+ l = __kfifo_peek_n(fifo, recsize);
+
+ if (l + recsize <= kfifo_len(fifo)) {
+ __kfifo_add_out(fifo, l + recsize);
+ return;
+ }
+ }
+ kfifo_reset_out(fifo);
+}
+
+/**
+ * kfifo_skip_rec - skip the next fifo out record
+ * @fifo: the fifo to be used.
+ * @recsize: size of record field
+ *
+ * This function skips the next FIFO record
+ */
+static inline void kfifo_skip_rec(struct kfifo *fifo,
+ unsigned int recsize)
+{
+ if (!__builtin_constant_p(recsize))
+ __kfifo_skip_generic(fifo, recsize);
+ else
+ __kfifo_skip_rec(fifo, recsize);
+}
+
+/**
+ * kfifo_avail_rec - returns the number of bytes available in a record FIFO
+ * @fifo: the fifo to be used.
+ * @recsize: size of record field
+ */
+static inline __must_check unsigned int kfifo_avail_rec(struct kfifo *fifo,
+ unsigned int recsize)
+{
+ unsigned int l = kfifo_size(fifo) - kfifo_len(fifo);
+
+ return (l > recsize) ? l - recsize : 0;
+}
+
#endif