X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fkfifo.c;h=2a78425ef67f323e8a967d14bc4515abf64e85aa;hb=a121f24accac1600bf5b6fb1e12eeabdfed7cb1a;hp=4950bdbe34772f92ee5780ed3858ace4d0624e3e;hpb=c1e13f25674ed564948ecb7dfe5f83e578892896;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/kfifo.c b/kernel/kfifo.c index 4950bdb..2a78425 100644 --- a/kernel/kfifo.c +++ b/kernel/kfifo.c @@ -26,6 +26,7 @@ #include #include #include +#include static void _kfifo_init(struct kfifo *fifo, unsigned char *buffer, unsigned int size) @@ -100,21 +101,37 @@ void kfifo_free(struct kfifo *fifo) EXPORT_SYMBOL(kfifo_free); /** - * __kfifo_put - puts some data into the FIFO, no locking version + * kfifo_skip - skip output data * @fifo: the fifo to be used. - * @buffer: the data to be added. + * @len: number of bytes to skip + */ +void kfifo_skip(struct kfifo *fifo, unsigned int len) +{ + if (len < kfifo_len(fifo)) { + __kfifo_add_out(fifo, len); + return; + } + kfifo_reset_out(fifo); +} +EXPORT_SYMBOL(kfifo_skip); + +/** + * kfifo_in - puts some data into the FIFO + * @fifo: the fifo to be used. + * @from: the data to be added. * @len: the length of the data to be added. * - * This function copies at most @len bytes from the @buffer into + * This function copies at most @len bytes from the @from buffer into * the FIFO depending on the free space, and returns the number of * bytes copied. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these functions. */ -unsigned int __kfifo_put(struct kfifo *fifo, - const unsigned char *buffer, 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(len, fifo->size - fifo->in + fifo->out); @@ -126,41 +143,37 @@ unsigned int __kfifo_put(struct kfifo *fifo, smp_mb(); + off = __kfifo_off(fifo, fifo->in); + /* first put the data starting from fifo->in to buffer end */ - l = min(len, fifo->size - (fifo->in & (fifo->size - 1))); - memcpy(fifo->buffer + (fifo->in & (fifo->size - 1)), buffer, l); + 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, buffer + l, len - l); - - /* - * Ensure that we add the bytes to the kfifo -before- - * we update the fifo->in index. - */ - - smp_wmb(); + memcpy(fifo->buffer, from + l, len - l); - fifo->in += len; + __kfifo_add_in(fifo, len); return len; } -EXPORT_SYMBOL(__kfifo_put); +EXPORT_SYMBOL(kfifo_in); /** - * __kfifo_get - gets some data from the FIFO, no locking version + * kfifo_out - gets some data from the FIFO * @fifo: the fifo to be used. - * @buffer: where the data must be copied. + * @to: where the data must be copied. * @len: the size of the destination buffer. * * This function copies at most @len bytes from the FIFO into the - * @buffer and returns the number of copied bytes. + * @to buffer and returns the number of copied bytes. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these functions. */ -unsigned int __kfifo_get(struct kfifo *fifo, - unsigned char *buffer, unsigned int len) +unsigned int kfifo_out(struct kfifo *fifo, + unsigned char *to, unsigned int len) { + unsigned int off; unsigned int l; len = min(len, fifo->in - fifo->out); @@ -172,22 +185,116 @@ unsigned int __kfifo_get(struct kfifo *fifo, 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 - (fifo->out & (fifo->size - 1))); - memcpy(buffer, fifo->buffer + (fifo->out & (fifo->size - 1)), l); + 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(buffer + l, fifo->buffer, len - l); + memcpy(to + l, fifo->buffer, len - l); + + __kfifo_add_out(fifo, len); + + return len; +} +EXPORT_SYMBOL(kfifo_out); + +/** + * kfifo_from_user - puts some data from user space into the FIFO + * @fifo: the fifo to be used. + * @from: pointer to the data to be added. + * @len: the length of the data to be added. + * + * This function copies at most @len bytes from the @from into the + * FIFO depending and returns the number of copied bytes. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these functions. + */ +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 remove the bytes from the kfifo -before- - * we update the fifo->out index. + * Ensure that we sample the fifo->out index -before- we + * start putting bytes into the kfifo. */ smp_mb(); - fifo->out += len; + 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; + + __kfifo_add_in(fifo, len); + + return len; +} +EXPORT_SYMBOL(kfifo_from_user); + +/** + * kfifo_to_user - gets data from the FIFO and write it to user space + * @fifo: the fifo to be used. + * @to: where the data must be copied. + * @len: the size of the destination buffer. + * + * This function copies at most @len bytes from the FIFO into the + * @to buffer and returns the number of copied bytes. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these functions. + */ +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; + + __kfifo_add_out(fifo, len); return len; } -EXPORT_SYMBOL(__kfifo_get); +EXPORT_SYMBOL(kfifo_to_user); +