s390/airq: add support for irq ranges
Add airq_iv_alloc and airq_iv_free to allocate and free consecutive
ranges of irqs from the interrupt vector.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/airq.c b/drivers/s390/cio/airq.c
index f055df0..445564c 100644
--- a/drivers/s390/cio/airq.c
+++ b/drivers/s390/cio/airq.c
@@ -186,55 +186,71 @@
EXPORT_SYMBOL(airq_iv_release);
/**
- * airq_iv_alloc_bit - allocate an irq bit from an interrupt vector
+ * airq_iv_alloc - allocate irq bits from an interrupt vector
* @iv: pointer to an interrupt vector structure
+ * @num: number of consecutive irq bits to allocate
*
- * Returns the bit number of the allocated irq, or -1UL if no bit
- * is available or the AIRQ_IV_ALLOC flag has not been specified
+ * Returns the bit number of the first irq in the allocated block of irqs,
+ * or -1UL if no bit is available or the AIRQ_IV_ALLOC flag has not been
+ * specified
*/
-unsigned long airq_iv_alloc_bit(struct airq_iv *iv)
+unsigned long airq_iv_alloc(struct airq_iv *iv, unsigned long num)
{
- unsigned long bit;
+ unsigned long bit, i;
- if (!iv->avail)
+ if (!iv->avail || num == 0)
return -1UL;
spin_lock(&iv->lock);
bit = find_first_bit_inv(iv->avail, iv->bits);
- if (bit < iv->bits) {
- clear_bit_inv(bit, iv->avail);
- if (bit >= iv->end)
- iv->end = bit + 1;
- } else
+ while (bit + num <= iv->bits) {
+ for (i = 1; i < num; i++)
+ if (!test_bit_inv(bit + i, iv->avail))
+ break;
+ if (i >= num) {
+ /* Found a suitable block of irqs */
+ for (i = 0; i < num; i++)
+ clear_bit_inv(bit + i, iv->avail);
+ if (bit + num >= iv->end)
+ iv->end = bit + num + 1;
+ break;
+ }
+ bit = find_next_bit_inv(iv->avail, iv->bits, bit + i + 1);
+ }
+ if (bit + num > iv->bits)
bit = -1UL;
spin_unlock(&iv->lock);
return bit;
}
-EXPORT_SYMBOL(airq_iv_alloc_bit);
+EXPORT_SYMBOL(airq_iv_alloc);
/**
- * airq_iv_free_bit - free an irq bit of an interrupt vector
+ * airq_iv_free - free irq bits of an interrupt vector
* @iv: pointer to interrupt vector structure
- * @bit: number of the irq bit to free
+ * @bit: number of the first irq bit to free
+ * @num: number of consecutive irq bits to free
*/
-void airq_iv_free_bit(struct airq_iv *iv, unsigned long bit)
+void airq_iv_free(struct airq_iv *iv, unsigned long bit, unsigned long num)
{
- if (!iv->avail)
+ unsigned long i;
+
+ if (!iv->avail || num == 0)
return;
spin_lock(&iv->lock);
- /* Clear (possibly left over) interrupt bit */
- clear_bit_inv(bit, iv->vector);
- /* Make the bit position available again */
- set_bit_inv(bit, iv->avail);
- if (bit == iv->end - 1) {
+ for (i = 0; i < num; i++) {
+ /* Clear (possibly left over) interrupt bit */
+ clear_bit_inv(bit + i, iv->vector);
+ /* Make the bit positions available again */
+ set_bit_inv(bit + i, iv->avail);
+ }
+ if (bit + num >= iv->end) {
/* Find new end of bit-field */
- while (--iv->end > 0)
- if (!test_bit_inv(iv->end - 1, iv->avail))
- break;
+ while (iv->end > 0 && !test_bit_inv(iv->end - 1, iv->avail))
+ iv->end--;
}
spin_unlock(&iv->lock);
}
-EXPORT_SYMBOL(airq_iv_free_bit);
+EXPORT_SYMBOL(airq_iv_free);
/**
* airq_iv_scan - scan interrupt vector for non-zero bits