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[80.187.83.189]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-426ce5cf6b4sm405958f8f.25.2025.10.09.12.13.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 09 Oct 2025 12:13:08 -0700 (PDT) Message-ID: Date: Thu, 9 Oct 2025 21:13:06 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/4] s390/sclp: Add support for dynamic (de)configuration of memory To: Sumanth Korikkar , Andrew Morton , linux-mm Cc: LKML , linux-s390 , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Alexander Gordeev References: <20251009131839.3739108-1-sumanthk@linux.ibm.com> <20251009131839.3739108-3-sumanthk@linux.ibm.com> From: David Hildenbrand Content-Language: en-US Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20251009131839.3739108-3-sumanthk@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Just a couple of nits > --- > drivers/s390/char/sclp_mem.c | 290 +++++++++++++++++++++++++---------- > 1 file changed, 207 insertions(+), 83 deletions(-) > > diff --git a/drivers/s390/char/sclp_mem.c b/drivers/s390/char/sclp_mem.c > index 27f49f5fd358..e1302b1c98ac 100644 > --- a/drivers/s390/char/sclp_mem.c > +++ b/drivers/s390/char/sclp_mem.c > @@ -9,9 +9,12 @@ > #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt > > #include > +#include > #include > #include > #include > +#include > +#include > #include > #include > #include > @@ -27,7 +30,6 @@ > #define SCLP_CMDW_ASSIGN_STORAGE 0x000d0001 > #define SCLP_CMDW_UNASSIGN_STORAGE 0x000c0001 > > -static DEFINE_MUTEX(sclp_mem_mutex); > static LIST_HEAD(sclp_mem_list); > static u8 sclp_max_storage_id; > static DECLARE_BITMAP(sclp_storage_ids, 256); > @@ -38,6 +40,18 @@ struct memory_increment { > int standby; > }; > > +struct sclp_mem { > + struct kobject kobj; > + unsigned int id; > + unsigned int memmap_on_memory; > + unsigned int config; > +}; > + > +struct sclp_mem_arg { > + struct sclp_mem *sclp_mems; > + struct kset *kset; > +}; Just one thought: if you keep either as global variable you wouldn't need this. (I would just keep both as globals, but whatever you prefer) Whatever you prefer. [...] > > -static void __init sclp_add_standby_memory(void) > +static int __init create_standby_sclp_mems(struct sclp_mem *sclp_mems, struct kset *kset) > { > struct memory_increment *incr; > + int rc = 0; > > list_for_each_entry(incr, &sclp_mem_list, list) { > if (incr->standby) > - add_memory_merged(incr->rn); > + rc = create_standby_sclp_mems_merged(sclp_mems, kset, incr->rn); > + if (rc) > + goto out; Why not "return rc;" to avoid the goto label? > } > - add_memory_merged(0); > + rc = create_standby_sclp_mems_merged(sclp_mems, kset, 0); > +out: > + return rc; > +} > + > +static int __init init_sclp_mem(void) > +{ > + const u64 block_size = memory_block_size_bytes(); Instead of "u64" maybe "unsigned long" like memory_block_size_bytes() returns? > + const u64 max_sclp_mems = roundup(sclp.rnmax * sclp.rzm, block_size) / block_size; Instead of u64 maybe "unsigned int" like the ids you store per sclp_mem? > + struct sclp_mem *sclp_mems; > + struct sclp_mem_arg arg; > + struct kset *kset; > + int rc; > + > + /* Allocate memory for all blocks ahead of time. */ > + sclp_mems = kcalloc(max_sclp_mems, sizeof(struct sclp_mem), GFP_KERNEL); > + if (!sclp_mems) > + return -ENOMEM; > + > + kset = kset_create_and_add("memory", NULL, firmware_kobj); > + if (!kset) > + return -ENOMEM; I guess we don't care about freeing sclp_mems in that case? Likely it should never ever happen either way. -- Cheers David / dhildenb