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New: there exists a wrong return value of function asd_map_memio() when ioremap_nocache() fails

Bug 106261 [email protected] 1 participant 2 messages Oct 19, 2015 SCSI

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https://bugzilla.kernel.org/show_bug.cgi?id=106261

Bug ID: 106261
Summary: there exists a wrong return value of function
asd_map_memio() when ioremap_nocache() fails
Product: SCSI Drivers
Version: 2.5
Kernel Version: 4.2
Hardware: All
OS: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: AIC94XX
Assignee: [email protected]
Reporter: [email protected]
Regression: No

In function asd_map_memio() at drivers/scsi/aic94xx/aic94xx_init.c:80, the call to ioremap() in line 104 and ioremap_nocache in line 107 may fail, and thus function asd_map_memio() will return the value of variable 'err'. And, the function asd_map_memio() will return 0 at last when it runs well. However, when the call to pci_request_region() in line 97 succeeds, the value of 'err' is 0. So the function asd_map_memio() will return 0 to its caller functions when it runs error because of the failing call to ioremap() or ioremap_nocache(), leading to a wrong return value in function asd_map_memio().
The related code snippets in asd_map_memio are as following. asd_map_memio @@drivers/scsi/aic94xx/aic94xx_init.c:80
80 static int asd_map_memio(struct asd_ha_struct *asd_ha)

 81 {
            ......

97 err = pci_request_region(asd_ha->pcidev, i,
ASD_DRIVER_NAME);
98 if (err) {
99 asd_printk("couldn't reserve memory region for
%s\n",
100 pci_name(asd_ha->pcidev));
101 goto Err;
102 }
103 if (io_handle->flags & IORESOURCE_CACHEABLE)
104 io_handle->addr = ioremap(io_handle->start,
105 io_handle->len);
106 else
107 io_handle->addr = ioremap_nocache(io_handle->start,
108 io_handle->len);
109 if (!io_handle->addr) {
110 asd_printk("couldn't map MBAR%d of %s\n", i==0?0:1,
111 pci_name(asd_ha->pcidev));
112 goto Err_unreq;
113 }
114 }
115
116 return 0;
117 Err_unreq:
118 pci_release_region(asd_ha->pcidev, i);
119 Err:
120 if (i > 0) {

121                 io_handle = &asd_ha->io_handle[0];
122                 iounmap(io_handle->addr);
123                 pci_release_region(asd_ha->pcidev, 0);

124 }
125 return err;
126 }

Generally, the return value of caller functions which call function ioremap_nocache() shall be set to a negative number when the call to ioremap_nocache() fails, like the following codes in another file. pmc_setup_dev @@arch/x86/kernel/pmc_atom.c:296
296 static int pmc_setup_dev(struct pci_dev *pdev)

297 {
            ......

312 pmc->regmap = ioremap_nocache(pmc->base_addr, PMC_MMIO_REG_LEN);
313 if (!pmc->regmap) {
314 dev_err(&pdev->dev, "error: ioremap failed\n");
315 return -ENOMEM;
316 }

            ......

327 }

Thank you

RUC_Soft_Sec

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