drbd: fix max_bio_size to be unsigned

We capped our max_bio_size respectively max_hw_sectors with
min_t(int, lower level limit, our limit);
unfortunately, some drivers, e.g. the kvm virtio block driver, initialize their
limits to "-1U", and that is of course a smaller "int" value than our limit.

Impact: we started to request 16 MB resync requests,
which lead to protocol error and a reconnect loop.

Fix all relevant constants and parameters to be unsigned int.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

3 files changed, 17 insertions, 15 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 2704af2ccf61..b2ca143d0053 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1136,8 +1136,8 @@ struct drbd_conf {
         int rs_in_flight; /* resync sectors in flight (to proxy, in proxy and from proxy) */
         int rs_planed;    /* resync sectors already planned */
         atomic_t ap_in_flight; /* App sectors in flight (waiting for ack) */
-        int peer_max_bio_size;
-        int local_max_bio_size;
+        unsigned int peer_max_bio_size;
+        unsigned int local_max_bio_size;
 };
 
 static inline struct drbd_conf *minor_to_mdev(unsigned int minor)
@@ -1441,9 +1441,9 @@ struct bm_extent {
  * hash table. */
 #define HT_SHIFT 8
 #define DRBD_MAX_BIO_SIZE (1U<<(9+HT_SHIFT))
-#define DRBD_MAX_BIO_SIZE_SAFE (1 << 12)       /* Works always = 4k */
+#define DRBD_MAX_BIO_SIZE_SAFE (1U << 12)       /* Works always = 4k */
 
-#define DRBD_MAX_SIZE_H80_PACKET (1 << 15) /* The old header only allows packets up to 32Kib data */
+#define DRBD_MAX_SIZE_H80_PACKET (1U << 15) /* The old header only allows packets up to 32Kib data */
 
 /* Number of elements in the app_reads_hash */
 #define APP_R_HSIZE 15
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 29a276425079..1ee1404769c2 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2209,7 +2209,8 @@ int drbd_send_sizes(struct drbd_conf *mdev, int trigger_reply, enum dds_flags fl
 {
         struct p_sizes p;
         sector_t d_size, u_size;
-        int q_order_type, max_bio_size;
+        int q_order_type;
+        unsigned int max_bio_size;
         int ok;
 
         if (get_ldev_if_state(mdev, D_NEGOTIATING)) {
@@ -2218,7 +2219,7 @@ int drbd_send_sizes(struct drbd_conf *mdev, int trigger_reply, enum dds_flags fl
                 u_size = mdev->ldev->dc.disk_size;
                 q_order_type = drbd_queue_order_type(mdev);
                 max_bio_size = queue_max_hw_sectors(mdev->ldev->backing_bdev->bd_disk->queue) << 9;
-                max_bio_size = min_t(int, max_bio_size, DRBD_MAX_BIO_SIZE);
+                max_bio_size = min(max_bio_size, DRBD_MAX_BIO_SIZE);
                 put_ldev(mdev);
         } else {
                 d_size = 0;
@@ -2229,7 +2230,7 @@ int drbd_send_sizes(struct drbd_conf *mdev, int trigger_reply, enum dds_flags fl
 
         /* Never allow old drbd (up to 8.3.7) to see more than 32KiB */
         if (mdev->agreed_pro_version <= 94)
-                max_bio_size = min_t(int, max_bio_size, DRBD_MAX_SIZE_H80_PACKET);
+                max_bio_size = min(max_bio_size, DRBD_MAX_SIZE_H80_PACKET);
 
         p.d_size = cpu_to_be64(d_size);
         p.u_size = cpu_to_be64(u_size);
@@ -3981,9 +3982,9 @@ int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
 
         spin_lock_irq(&mdev->req_lock);
         if (mdev->state.conn < C_CONNECTED) {
-                int peer;
+                unsigned int peer;
                 peer = be32_to_cpu(buffer->la_peer_max_bio_size);
-                peer = max_t(int, peer, DRBD_MAX_BIO_SIZE_SAFE);
+                peer = max(peer, DRBD_MAX_BIO_SIZE_SAFE);
                 mdev->peer_max_bio_size = peer;
         }
         spin_unlock_irq(&mdev->req_lock);
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index c47df7cf7f80..fb9dce8daa24 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -801,8 +801,8 @@ static int drbd_check_al_size(struct drbd_conf *mdev)
 static void drbd_setup_queue_param(struct drbd_conf *mdev, unsigned int max_bio_size)
 {
         struct request_queue * const q = mdev->rq_queue;
-        int max_hw_sectors = max_bio_size >> 9;
-        int max_segments = 0;
+        unsigned int max_hw_sectors = max_bio_size >> 9;
+        unsigned int max_segments = 0;
 
         if (get_ldev_if_state(mdev, D_ATTACHING)) {
                 struct request_queue * const b = mdev->ldev->backing_bdev->bd_disk->queue;
@@ -835,7 +835,7 @@ static void drbd_setup_queue_param(struct drbd_conf *mdev, unsigned int max_bio_
 
 void drbd_reconsider_max_bio_size(struct drbd_conf *mdev)
 {
-        int now, new, local, peer;
+        unsigned int now, new, local, peer;
 
         now = queue_max_hw_sectors(mdev->rq_queue) << 9;
         local = mdev->local_max_bio_size; /* Eventually last known value, from volatile memory */
@@ -846,13 +846,14 @@ void drbd_reconsider_max_bio_size(struct drbd_conf *mdev)
                 mdev->local_max_bio_size = local;
                 put_ldev(mdev);
         }
+        local = min(local, DRBD_MAX_BIO_SIZE);
 
         /* We may ignore peer limits if the peer is modern enough.
            Because new from 8.3.8 onwards the peer can use multiple
            BIOs for a single peer_request */
         if (mdev->state.conn >= C_CONNECTED) {
                 if (mdev->agreed_pro_version < 94) {
-                        peer = min_t(int, mdev->peer_max_bio_size, DRBD_MAX_SIZE_H80_PACKET);
+                        peer = min(mdev->peer_max_bio_size, DRBD_MAX_SIZE_H80_PACKET);
                         /* Correct old drbd (up to 8.3.7) if it believes it can do more than 32KiB */
                 } else if (mdev->agreed_pro_version == 94)
                         peer = DRBD_MAX_SIZE_H80_PACKET;
@@ -860,10 +861,10 @@ void drbd_reconsider_max_bio_size(struct drbd_conf *mdev)
                         peer = DRBD_MAX_BIO_SIZE;
         }
 
-        new = min_t(int, local, peer);
+        new = min(local, peer);
 
         if (mdev->state.role == R_PRIMARY && new < now)
-                dev_err(DEV, "ASSERT FAILED new < now; (%d < %d)\n", new, now);
+                dev_err(DEV, "ASSERT FAILED new < now; (%u < %u)\n", new, now);
 
         if (new != now)
                 dev_info(DEV, "max BIO size = %u\n", new);