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>
diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h
index d3230fb..486e8ad 100644
--- a/include/linux/kfifo.h
+++ b/include/linux/kfifo.h
@@ -278,4 +278,334 @@
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
diff --git a/kernel/kfifo.c b/kernel/kfifo.c
index 2a78425..e92d519 100644
--- a/kernel/kfifo.c
+++ b/kernel/kfifo.c
@@ -115,6 +115,113 @@
}
EXPORT_SYMBOL(kfifo_skip);
+static inline void __kfifo_in_data(struct kfifo *fifo,
+ const void *from, unsigned int len, unsigned int off)
+{
+ unsigned int l;
+
+ /*
+ * Ensure that we sample the fifo->out index -before- we
+ * start putting bytes into the kfifo.
+ */
+
+ smp_mb();
+
+ off = __kfifo_off(fifo, fifo->in + off);
+
+ /* first put the data starting from fifo->in to buffer end */
+ l = min(len, fifo->size - off);
+ memcpy(fifo->buffer + off, from, l);
+
+ /* then put the rest (if any) at the beginning of the buffer */
+ memcpy(fifo->buffer, from + l, len - l);
+}
+
+static inline void __kfifo_out_data(struct kfifo *fifo,
+ void *to, unsigned int len, unsigned int off)
+{
+ unsigned int l;
+
+ /*
+ * Ensure that we sample the fifo->in index -before- we
+ * start removing bytes from the kfifo.
+ */
+
+ smp_rmb();
+
+ off = __kfifo_off(fifo, fifo->out + off);
+
+ /* first get the data from fifo->out until the end of the buffer */
+ l = min(len, fifo->size - off);
+ memcpy(to, fifo->buffer + off, l);
+
+ /* then get the rest (if any) from the beginning of the buffer */
+ memcpy(to + l, fifo->buffer, len - l);
+}
+
+static inline unsigned int __kfifo_from_user_data(struct kfifo *fifo,
+ const void __user *from, unsigned int len, unsigned int off)
+{
+ unsigned int l;
+ int ret;
+
+ /*
+ * Ensure that we sample the fifo->out index -before- we
+ * start putting bytes into the kfifo.
+ */
+
+ smp_mb();
+
+ off = __kfifo_off(fifo, fifo->in + off);
+
+ /* first put the data starting from fifo->in to buffer end */
+ l = min(len, fifo->size - off);
+ ret = copy_from_user(fifo->buffer + off, from, l);
+
+ if (unlikely(ret))
+ return ret + len - l;
+
+ /* then put the rest (if any) at the beginning of the buffer */
+ return copy_from_user(fifo->buffer, from + l, len - l);
+}
+
+static inline unsigned int __kfifo_to_user_data(struct kfifo *fifo,
+ void __user *to, unsigned int len, unsigned int off)
+{
+ unsigned int l;
+ int ret;
+
+ /*
+ * Ensure that we sample the fifo->in index -before- we
+ * start removing bytes from the kfifo.
+ */
+
+ smp_rmb();
+
+ off = __kfifo_off(fifo, fifo->out + off);
+
+ /* first get the data from fifo->out until the end of the buffer */
+ l = min(len, fifo->size - off);
+ ret = copy_to_user(to, fifo->buffer + off, l);
+
+ if (unlikely(ret))
+ return ret + len - l;
+
+ /* then get the rest (if any) from the beginning of the buffer */
+ return copy_to_user(to + l, fifo->buffer, len - l);
+}
+
+unsigned int __kfifo_in_n(struct kfifo *fifo,
+ const void *from, unsigned int len, unsigned int recsize)
+{
+ if (kfifo_avail(fifo) < len + recsize)
+ return len + 1;
+
+ __kfifo_in_data(fifo, from, len, recsize);
+ return 0;
+}
+EXPORT_SYMBOL(__kfifo_in_n);
+
/**
* kfifo_in - puts some data into the FIFO
* @fifo: the fifo to be used.
@@ -128,36 +235,36 @@
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
*/
-unsigned int kfifo_in(struct kfifo *fifo,
- const unsigned char *from, unsigned int len)
+unsigned int kfifo_in(struct kfifo *fifo, const unsigned char *from,
+ unsigned int len)
{
- unsigned int off;
- unsigned int l;
+ len = min(kfifo_avail(fifo), len);
- len = min(len, fifo->size - fifo->in + fifo->out);
-
- /*
- * Ensure that we sample the fifo->out index -before- we
- * start putting bytes into the kfifo.
- */
-
- smp_mb();
-
- off = __kfifo_off(fifo, fifo->in);
-
- /* first put the data starting from fifo->in to buffer end */
- l = min(len, fifo->size - off);
- memcpy(fifo->buffer + off, from, l);
-
- /* then put the rest (if any) at the beginning of the buffer */
- memcpy(fifo->buffer, from + l, len - l);
-
+ __kfifo_in_data(fifo, from, len, 0);
__kfifo_add_in(fifo, len);
-
return len;
}
EXPORT_SYMBOL(kfifo_in);
+unsigned int __kfifo_in_generic(struct kfifo *fifo,
+ const void *from, unsigned int len, unsigned int recsize)
+{
+ return __kfifo_in_rec(fifo, from, len, recsize);
+}
+EXPORT_SYMBOL(__kfifo_in_generic);
+
+unsigned int __kfifo_out_n(struct kfifo *fifo,
+ void *to, unsigned int len, unsigned int recsize)
+{
+ if (kfifo_len(fifo) < len + recsize)
+ return len;
+
+ __kfifo_out_data(fifo, to, len, recsize);
+ __kfifo_add_out(fifo, len + recsize);
+ return 0;
+}
+EXPORT_SYMBOL(__kfifo_out_n);
+
/**
* kfifo_out - gets some data from the FIFO
* @fifo: the fifo to be used.
@@ -170,36 +277,35 @@
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
*/
-unsigned int kfifo_out(struct kfifo *fifo,
- unsigned char *to, unsigned int len)
+unsigned int kfifo_out(struct kfifo *fifo, unsigned char *to, unsigned int len)
{
- unsigned int off;
- unsigned int l;
+ len = min(kfifo_len(fifo), len);
- len = min(len, fifo->in - fifo->out);
-
- /*
- * Ensure that we sample the fifo->in index -before- we
- * start removing bytes from the kfifo.
- */
-
- smp_rmb();
-
- off = __kfifo_off(fifo, fifo->out);
-
- /* first get the data from fifo->out until the end of the buffer */
- l = min(len, fifo->size - off);
- memcpy(to, fifo->buffer + off, l);
-
- /* then get the rest (if any) from the beginning of the buffer */
- memcpy(to + l, fifo->buffer, len - l);
-
+ __kfifo_out_data(fifo, to, len, 0);
__kfifo_add_out(fifo, len);
return len;
}
EXPORT_SYMBOL(kfifo_out);
+unsigned int __kfifo_out_generic(struct kfifo *fifo,
+ void *to, unsigned int len, unsigned int recsize,
+ unsigned int *total)
+{
+ return __kfifo_out_rec(fifo, to, len, recsize, total);
+}
+EXPORT_SYMBOL(__kfifo_out_generic);
+
+unsigned int __kfifo_from_user_n(struct kfifo *fifo,
+ const void __user *from, unsigned int len, unsigned int recsize)
+{
+ if (kfifo_avail(fifo) < len + recsize)
+ return len + 1;
+
+ return __kfifo_from_user_data(fifo, from, len, recsize);
+}
+EXPORT_SYMBOL(__kfifo_from_user_n);
+
/**
* kfifo_from_user - puts some data from user space into the FIFO
* @fifo: the fifo to be used.
@@ -215,40 +321,38 @@
unsigned int kfifo_from_user(struct kfifo *fifo,
const void __user *from, unsigned int len)
{
- unsigned int off;
- unsigned int l;
- int ret;
-
- len = min(len, fifo->size - fifo->in + fifo->out);
-
- /*
- * Ensure that we sample the fifo->out index -before- we
- * start putting bytes into the kfifo.
- */
-
- smp_mb();
-
- off = __kfifo_off(fifo, fifo->in);
-
- /* first put the data starting from fifo->in to buffer end */
- l = min(len, fifo->size - off);
- ret = copy_from_user(fifo->buffer + off, from, l);
-
- if (unlikely(ret))
- return l - ret;
-
- /* then put the rest (if any) at the beginning of the buffer */
- ret = copy_from_user(fifo->buffer, from + l, len - l);
-
- if (unlikely(ret))
- return len - ret;
-
+ len = min(kfifo_avail(fifo), len);
+ len -= __kfifo_from_user_data(fifo, from, len, 0);
__kfifo_add_in(fifo, len);
-
return len;
}
EXPORT_SYMBOL(kfifo_from_user);
+unsigned int __kfifo_from_user_generic(struct kfifo *fifo,
+ const void __user *from, unsigned int len, unsigned int recsize)
+{
+ return __kfifo_from_user_rec(fifo, from, len, recsize);
+}
+EXPORT_SYMBOL(__kfifo_from_user_generic);
+
+unsigned int __kfifo_to_user_n(struct kfifo *fifo,
+ void __user *to, unsigned int len, unsigned int reclen,
+ unsigned int recsize)
+{
+ unsigned int ret;
+
+ if (kfifo_len(fifo) < reclen + recsize)
+ return len;
+
+ ret = __kfifo_to_user_data(fifo, to, reclen, recsize);
+
+ if (likely(ret == 0))
+ __kfifo_add_out(fifo, reclen + recsize);
+
+ return ret;
+}
+EXPORT_SYMBOL(__kfifo_to_user_n);
+
/**
* kfifo_to_user - gets data from the FIFO and write it to user space
* @fifo: the fifo to be used.
@@ -264,37 +368,33 @@
unsigned int kfifo_to_user(struct kfifo *fifo,
void __user *to, unsigned int len)
{
- unsigned int off;
- unsigned int l;
- int ret;
-
- len = min(len, fifo->in - fifo->out);
-
- /*
- * Ensure that we sample the fifo->in index -before- we
- * start removing bytes from the kfifo.
- */
-
- smp_rmb();
-
- off = __kfifo_off(fifo, fifo->out);
-
- /* first get the data from fifo->out until the end of the buffer */
- l = min(len, fifo->size - off);
- ret = copy_to_user(to, fifo->buffer + off, l);
-
- if (unlikely(ret))
- return l - ret;
-
- /* then get the rest (if any) from the beginning of the buffer */
- ret = copy_to_user(to + l, fifo->buffer, len - l);
-
- if (unlikely(ret))
- return len - ret;
-
+ len = min(kfifo_len(fifo), len);
+ len -= __kfifo_to_user_data(fifo, to, len, 0);
__kfifo_add_out(fifo, len);
-
return len;
}
EXPORT_SYMBOL(kfifo_to_user);
+unsigned int __kfifo_to_user_generic(struct kfifo *fifo,
+ void __user *to, unsigned int len, unsigned int recsize,
+ unsigned int *total)
+{
+ return __kfifo_to_user_rec(fifo, to, len, recsize, total);
+}
+EXPORT_SYMBOL(__kfifo_to_user_generic);
+
+unsigned int __kfifo_peek_generic(struct kfifo *fifo, unsigned int recsize)
+{
+ if (recsize == 0)
+ return kfifo_avail(fifo);
+
+ return __kfifo_peek_n(fifo, recsize);
+}
+EXPORT_SYMBOL(__kfifo_peek_generic);
+
+void __kfifo_skip_generic(struct kfifo *fifo, unsigned int recsize)
+{
+ __kfifo_skip_rec(fifo, recsize);
+}
+EXPORT_SYMBOL(__kfifo_skip_generic);
+