[patch V3 09/10] scsi: ufs: qcom: Remove the MSI descriptor abuse

Thomas Gleixner
2025-03-17T13:29:33Z

The driver abuses the MSI descriptors for internal purposes. Aside of core
code and MSI providers nothing has to care about their existence. They have
been encapsulated with a lot of effort because this kind of abuse caused
all sorts of issues including a maintainability nightmare.

Rewrite the code so it uses dedicated storage to hand the required
information to the interrupt handler.

No functional change intended.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org

---
drivers/ufs/host/ufs-qcom.c | 77 ++++++++++++++++++++++----------------------
1 file changed, 40 insertions(+), 37 deletions(-)

--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -1782,15 +1782,19 @@ static void ufs_qcom_write_msi_msg(struc
ufshcd_mcq_config_esi(hba, msg);
}

+struct ufs_qcom_irq {
+ unsigned int irq;
+ unsigned int idx;
+ struct ufs_hba *hba;
+};
+
static irqreturn_t ufs_qcom_mcq_esi_handler(int irq, void *data)
{
- struct msi_desc *desc = data;
- struct device *dev = msi_desc_to_dev(desc);
- struct ufs_hba *hba = dev_get_drvdata(dev);
- u32 id = desc->msi_index;
- struct ufs_hw_queue *hwq = &hba->uhq[id];
+ struct ufs_qcom_irq *qi = data;
+ struct ufs_hba *hba = qi->hba;
+ struct ufs_hw_queue *hwq = &hba->uhq[qi->idx];

- ufshcd_mcq_write_cqis(hba, 0x1, id);
+ ufshcd_mcq_write_cqis(hba, 0x1, qi->idx);
ufshcd_mcq_poll_cqe_lock(hba, hwq);

return IRQ_HANDLED;
@@ -1799,8 +1803,7 @@ static irqreturn_t ufs_qcom_mcq_esi_hand
static int ufs_qcom_config_esi(struct ufs_hba *hba)
{
struct ufs_qcom_host *host = ufshcd_get_variant(hba);
- struct msi_desc *desc;
- struct msi_desc *failed_desc = NULL;
+ struct ufs_qcom_irq *qi;
int nr_irqs, ret;

if (host->esi_enabled)
@@ -1811,47 +1814,47 @@ static int ufs_qcom_config_esi(struct uf
* 2. Poll queues do not need ESI.
*/
nr_irqs = hba->nr_hw_queues - hba->nr_queues[HCTX_TYPE_POLL];
+ qi = devm_kcalloc(hba->dev, nr_irqs, sizeof(*qi), GFP_KERNEL);
+ if (qi)
+ return -ENOMEM;
+
ret = platform_device_msi_init_and_alloc_irqs(hba->dev, nr_irqs,
ufs_qcom_write_msi_msg);
if (ret) {
dev_err(hba->dev, "Failed to request Platform MSI %d\n", ret);
- return ret;
+ goto cleanup;
}

- msi_lock_descs(hba->dev);
- msi_for_each_desc(desc, hba->dev, MSI_DESC_ALL) {
- ret = devm_request_irq(hba->dev, desc->irq,
- ufs_qcom_mcq_esi_handler,
- IRQF_SHARED, "qcom-mcq-esi", desc);
+ for (int idx = 0; idx < nr_irqs; idx++) {
+ qi[idx].irq = msi_get_virq(hba->dev, idx);
+ qi[idx].idx = idx;
+ qi[idx].hba = hba;
+
+ ret = devm_request_irq(hba->dev, qi[idx].irq, ufs_qcom_mcq_esi_handler,
+ IRQF_SHARED, "qcom-mcq-esi", qi + idx);
if (ret) {
dev_err(hba->dev, "%s: Fail to request IRQ for %d, err = %d\n",
- __func__, desc->irq, ret);
- failed_desc = desc;
- break;
+ __func__, qi[idx].irq, ret);
+ qi[idx].irq = 0;
+ goto cleanup;
}
}
- msi_unlock_descs(hba->dev);

- if (ret) {
- /* Rewind */
- msi_lock_descs(hba->dev);
- msi_for_each_desc(desc, hba->dev, MSI_DESC_ALL) {
- if (desc == failed_desc)
- break;
- devm_free_irq(hba->dev, desc->irq, hba);
- }
- msi_unlock_descs(hba->dev);
- platform_device_msi_free_irqs_all(hba->dev);
- } else {
- if (host->hw_ver.major == 6 && host->hw_ver.minor == 0 &&
- host->hw_ver.step == 0)
- ufshcd_rmwl(hba, ESI_VEC_MASK,
- FIELD_PREP(ESI_VEC_MASK, MAX_ESI_VEC - 1),
- REG_UFS_CFG3);
- ufshcd_mcq_enable_esi(hba);
- host->esi_enabled = true;
+ if (host->hw_ver.major == 6 && host->hw_ver.minor == 0 &&
+ host->hw_ver.step == 0) {
+ ufshcd_rmwl(hba, ESI_VEC_MASK,
+ FIELD_PREP(ESI_VEC_MASK, MAX_ESI_VEC - 1),
+ REG_UFS_CFG3);
}
-
+ ufshcd_mcq_enable_esi(hba);
+ host->esi_enabled = true;
+ return 0;
+
+cleanup:
+ for (int idx = 0; qi[idx].irq; idx++)
+ devm_free_irq(hba->dev, qi[idx].irq, hba);
+ platform_device_msi_free_irqs_all(hba->dev);
+ devm_kfree(hba->dev, qi);
return ret;
}