qed: Don't use main-ptt in unrelated flows

In order to access HW registers driver needs to acquire a PTT entry
[mapping between bar memory and internal chip address].
Since acquiring PTT entries could fail [at least in theory] as their
number is finite and other flows can hold them, we reserve special PTT
entries for 'important' enough flows - ones we want to guarantee that
would not be susceptible to such issues.

One such special entry is the 'main' PTT which is meant to be used in
flows such as chip initialization and de-initialization.
However, there are other flows that are also using that same entry
for their own purpose, and might run concurrently with the original
flows [notice that for most cases using the main-ptt by mistake, such
a race is still impossible, at least today].

This patch re-organizes the various functions that currently use the
main_ptt in one of two ways:

  - If a function shouldn't use the main_ptt it starts acquiring and
    releasing it's own PTT entry and use it instead. Notice if those
    functions previously couldn't fail, they now can [as acquisition
    might fail].

  - Change the prototypes so that the main_ptt would be received as
    a parameter [instead of explicitly accessing it].
    This prevents the future risk of adding codes that introduces new
    use-cases for flows using the main_ptt, ones that might be in race
    with the actual 'main' flows.

Signed-off-by: Rahul Verma <Rahul.Verma@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/net/ethernet/qlogic/qed/qed_fcoe.c b/drivers/net/ethernet/qlogic/qed/qed_fcoe.c
index f4b95345d1a5..21a58fffd02b 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_fcoe.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_fcoe.c
@@ -340,10 +340,10 @@ qed_sp_fcoe_conn_destroy(struct qed_hwfn *p_hwfn,
 
 static int
 qed_sp_fcoe_func_stop(struct qed_hwfn *p_hwfn,
+		      struct qed_ptt *p_ptt,
 		      enum spq_mode comp_mode,
 		      struct qed_spq_comp_cb *p_comp_addr)
 {
-	struct qed_ptt *p_ptt = p_hwfn->p_main_ptt;
 	struct qed_spq_entry *p_ent = NULL;
 	struct qed_sp_init_data init_data;
 	u32 active_segs = 0;
@@ -765,6 +765,7 @@ static struct qed_hash_fcoe_con *qed_fcoe_get_hash(struct qed_dev *cdev,
 
 static int qed_fcoe_stop(struct qed_dev *cdev)
 {
+	struct qed_ptt *p_ptt;
 	int rc;
 
 	if (!(cdev->flags & QED_FLAG_STORAGE_STARTED)) {
@@ -778,10 +779,15 @@ static int qed_fcoe_stop(struct qed_dev *cdev)
 		return -EINVAL;
 	}
 
+	p_ptt = qed_ptt_acquire(QED_LEADING_HWFN(cdev));
+	if (!p_ptt)
+		return -EAGAIN;
+
 	/* Stop the fcoe */
-	rc = qed_sp_fcoe_func_stop(QED_LEADING_HWFN(cdev),
+	rc = qed_sp_fcoe_func_stop(QED_LEADING_HWFN(cdev), p_ptt,
 				   QED_SPQ_MODE_EBLOCK, NULL);
 	cdev->flags &= ~QED_FLAG_STORAGE_STARTED;
+	qed_ptt_release(QED_LEADING_HWFN(cdev), p_ptt);
 
 	return rc;
 }